Intro
These are the kinds of IEMs that impress you when you see them, then sorely disappoint once you pick them up. All until you actually listen to them and are floored once again. Please note, this is an update/edit of the review and initial impressions I gave on Massdrop here.

Aesthetics - 8.0/10
Despite what looks like cheap materials, these are some really, really, sharp looking IEMs. They've ditched the "professional" design found on many of it's competitors (I'm looking at you, Shure) for some colourful and even relatively stylish buds. The blue is really a pretty shade and the black and silver face-plate looks great when the paint is still all there.

Fit - 7.5/10
The silicone tips are fairly soft and the foam tips are functional and non-abrasive. It's particularly noteworthy that Ultimate Ears includes a full second set of tips, attached to little sticks (that are removable) to be used to find the perfect fit for your ears.. That said, I would suggest making an investment in aftermarket eartips (such as Comply - myself using T200) . The body of the IEM doesn't fit nearly as flush as some of it's competitors (i.e., Westone, Shure, etc.) but still overall it's sufficiently comfortable.

Build - 5.2/10
I may be wrong but everything seems to be made out of fairly simple, cheap plastics. Every part feels sturdy enough but that's about it, nothing feels quite as premium as it's MSRP would imply. That said, nothing felt particularly cheap either. One major point of contention for me is the paint on the face-plates of the earbuds, as after only a few months of use they've worn away quite a bit and it's left my earbuds look quite bad. Had I paid full MSRP for these, I would be truly livid with how they've held up, but considering I got them below half-price on Massdrop I'm not all that bothered.

Sound - 9.1/10
After giving these earbuds more than 250 hours (honestly It's probably closer to 400 hours), here are my thoughts on sound.

Sub-Bass:
As one would assume, with a dedicated sub-bass driver, it would sound pretty good. And that assumption is not wrong, as the sub-bass is both impactful and fast, really fast. I was quite impressed with the power and extension of these buds. I find Jazz, Soul, and some Electronic music really show off this aspect.

Bass:
The bass on these IEMs continue to have solid punch and detail. It also comes across with moderate amount character (this may or may not be a good thing depending on how analytical you want your IEMs to be) which makes it nearly playful when listening. They still give you a reference level of precision, but there is a slight warmth to these IEMs which really makes them geared more specifically to listening than producing.

Click here for an example that plays very nicely with the bass and sub-bass driver of these IEMs.

Mids:
They're present, but definitively less than impacful. The mids are not BAD per se but they don't leave much of an impression. These earbuds have a subtle V-shaped sound signature so if you listen to a lot of music with prominent female vocals, these might not do you right. Despite this, the mids are still as detailed as any other part of the spectrum, if not a little bland and recessed when compared with the rest of the sound.

Highs:
The highs are crisp and detailed while still keeping a lid on things, never becoming sibilant or too sharp. They aren't quite as precise as some other high-end IEMs but you defintely won't find yourself disappointed with the highs on these buds.

Sound Stage:
For IEMs, these produce such a wide sound stage it is surprising. Many of my friends have stated that it sounds like you're wearing much larger cans and I for one definitely agree. Despite providing a large sound stage for earbuds, it is still only large for earbuds and won't take on some great open-backed headphones. Regardless, Ultimate Ears really made the best of what they could with the physical limitations at hand.

Imaging:
Even if the sound stage may be tight when compared to some larger headphones, the work that the 900s do in this space is nothing short of witchcraft. The stereo imaging is superb if not perfect. The level of instrument separation is as good if not better than nearly any other in-ear headphone I've ever heard.

Overall - 8.1/10
Despite having relatively low scores in both Fit as well as Build Quality, sound quality is paramount to everything for me and these headphones has great sound in spades.

Initial impressions:
Wow. These are some good-looking, simple, minimalist, headphones. They feel sturdy and light thanks to good choices in material and they've definitely turned some heads as I wear them around campus. Also, these are hands-down the most comfortable on-ear headphones in history.
 
Aesthetics:
This is one of the best parts of the headphones. They look sleek and modern. Minimalist and humble yet definitely premium looking. The body is constructed entirely from leather and aluminum which immediately helps them look different from most.
 
Build Quality:
Excellent. Simple construction of aluminum and leather helps keep things sturdy. They have a unique hinge design which seems to put minimal stress on the wire which is also a big plus. Overall, assuming you don't abuse the headphones, they should last you an eternity.
 
Sound Quality:
Very good. The first thing you'll notice about the sound is that it doesn't sound like headphones. It sounds like you're wearing a pair of KEF speakers on your ears (likely because you're wearing a portable pair of KEF speakers). Once you're used to the interesting voicing, you'll note their fairly neutral with a slightly dark slant. Everything is very powerful and punchy, the bass extends very deep without ever getting muddy and the highs are always crisp. On top of this, they don't fall apart at higher volumes, everything coming together to make these a very impressive sounding pair of cans.  
Sound Signature:
Mostly neutral with a somewhat dark slant. No dramatic rolloffs anywhere with great extension in both directions.
Graph below:

 
Overall:
Awesome headphones, awesome sound, awesome look.

Initial impressions:
When I first held these, they scared the pants off me. The cups wiggled a little bit and the yokes connecting the cups and the headband were attached in such a way that I felt if I were to move them wrong they'd just fall apart. After using them for a while I came to get used to these design choices and accept that it's pretty stable and well built, but they feel flimsy as all heck and still make me feel a bit unsure from time to time.
 
Aesthetics:
They look like headphones with slats on the sides. The aesthetic design leaves a fair bit to be desired. They have a bare-bones, utilitarian design with the only feature of luxury being the velour earpads and plush headband. Round plastic cups with a metal yoke to a foam and plastic headband. It's pretty straightforward.
 
Build Quality:
These headphones seem to be of high build quality though some of the material choices concern me. Many of the parts, especially parts that move, are simply brittle plastic which makes me concerned for long-term reliability. Aside from that, everything seems to be assembled with care and it seems pretty solid.
 
Sound Quality:
This is the real reason anyone buys a Beyerdynamic headphone. The sound on these is far better than their pricetag would imply. They have clean bass and sparkling highs which gives music a somewhat magical and mystical feeling. The midrange lacks a bit of richness or fullness but that can be mostly remedied with an equalizer. Additionally, it is a bit weaker in terms of detail when compared to other top competitors at the price range and when listening to complex music (e.g., Radiohead - The National Anthem) it starts to lose control and provide sloppy bass.
On the other hand, these headphones scale incredibly well. I was given the privilege of being able to listen to these while plugged into a Schiit Ragnarok and Yggdrasil and they performed in a way that you could expect of $500 or $600 headphones. It was simply astounding, so if you want headphones that will keep rising to the occasion when you upgrade your components, these might just be for you.
 
Sound Signature:
These headphones have a somewhat V-shaped sound signature in that can be seen below:

 
Overall:
These are good sounding headphones for a super competitive price that are comfortable to wear, scale well, and have a massive soundstage. If you can get past some interesting design choices, these are definitely among the best in its price range.

Initial Impression:
Immediately upon seeing these, many moons past, it was very funky. The black and hot pink colour scheme stood out and they seemed very cool, more so than anything else. They felt very good to the touch with the rough fabric-like dome covers and I was immensely impressed with the bungee cord that loops around the cable where it plugs into the headphone.
 
Aesthetics:
These are designed to be flashy and funky. They're made to draw attention to the wearer and to themselves as they are large, black and hot pink. On the domes, there is a grey design to keep it from being boring whatsoever and overall they are good-looking though obnoxious.
 
Build Quality:
Over the three years that I have owned them, they have held together quite well in typical Sony fashion. The cable has been good and the only degradation I've found it the little plastic-y decals on the domes have started to fall off. The headphones feel strong and sturdy though they don't collapse or do any tricks with the earcups.
 
Comfort:
These headphones are NOT comfortable at all. The pads are firm and the plastic is not soft. The headband is lined with hard nubs for no conceivable reason. The pads are very short too leading your ears to go right up against the inner wall of the earcup. The only thing that makes them at all bearable to wear is how light they are (approximately 9oz).
 
Sound Quality:
They sound like any other decent $100 headphone except these sacrifice a little it of the mids and highs to get some massive bass. Now most affordable headphones have low impedance but these don't. At a hearty 70 ohms, they don't sound awful unpowered but they definitely improve a lot from a decent amplifier.
 
Sound Signature:
These headphones are a budget basshead's dream. Costing only $100 (at most), these deliver very powerful bass in return for quieter (but well executed) highs and tinny and recessed mids. It's like a v-shaped sound signature that is tilted a little to the right.
 
Overall:
These headphones wouldn't know what subtle is if it was hit over the head with subtlety itself. Whether it's the obnoxious looks or obnoxious sound, these are very in-your-face and very good value.

Initial Impression:
They're earbuds with funky tips. They have a funky black and white wire and they're decently popular. Initially they appeared as good earbuds with a very consumer-friendly sound.
 
Build Quality:
The build quality is very poor. It's made from cheap plastics which tend to break under ANY level of impact. Parts of the bud can fairly easily shake loose leaving you with rattling noises whenever you move or lower frequencies are made. The tips are also made from a cheap silicone and tend to start to split and form fissures after regular wear and tear of a few months.
 
Aesthetics:
These look slick. The spiraled black and white wire looks really cool, the chrome (or faux-chrome?) on the outside of the buds make them look cool and the weirdly shaped tips actually look quite natural in their translucent form.
 
Sound Quality:
Simply put, the sound quality of these are decent. If you're moving up from your free earbuds that come with your phone, then these are fantastic. In fact, these are better than most things under $60. That said, you're paying the BOSE tax (similar to the Apple tax or the Beats tax) in which you're paying for the brand name. It doesn't perform nearly as well as any of the single-driver IEMs which run a similar cost. At best, they sound about as good as the beats earbuds.
 
Sound Signature:
This sound signature is so sculpted you might think it was made of clay... In all seriousness though, it is incredibly unnatural. Huge bass boost with upper-range equalization as an attempt to minimize upper-end rolloff. All of this to find yourself listening to earbuds that sound a lot like Beats Solos.
 
Overall:
Decent headphones but bad for the price.

Initial Impression:
Even the unboxing experience was great. Everything was neatly presented, it came with a certificate of authenticity, and even the cardboard(?) they used for the box was smooth and pleasant to touch. The headphones immediately had a premium look and feel, from the lack of visible plastic to the addition of the ebony wood veneer.
 
Build Quality:
The build quality of these headphones is simply fantastic. Everything is perfectly in place, nothing is misaligned, it seems that great care was put into the assembly of these headphones. The die-cast metal seems very sturdy so far and the lambskin leather looks as if it were new despite exposure to sweaty ears or cold temperatures. I've only had these headphones for roughly a month now (October 20th), but I expect these to hold together quite well based on what I've seen so far.
 
Aesthetics:
Aesthetics is a completely subjective area and so to address this, I will just provide a combination of my and my friend's opinion.
My opinion: It is, very literally, a BMW for your ears. Designed by BMW DesignWorks USA, it is a combination of the circles-and-contours design language found on the beautiful BMW cars as well as the traditional Audeze wood-and-metal design found in the LCD lineup. I find it to be the most attractive headphone Audeze makes and everyone I've shown them to, regardless of their audio-gear knowledge, think they're very attractive and luxurious (if not large).
My friend's opinion: These headphones represent the epitome of quality for an extraordinary price.  Aesthetically, they are extraordinarily pleasing, comporting beautiful contours, and designed extremely precisely so everything looks exactly in the proper place.  The instruments consist of wooden highlights which provide a wonderful natural look.  The ear pads are of a luxurious leather which feel like one just enclosed the ears with soft soothing comfort and enhance the high end appearance of the headphones.  Truly a superior aesthetically pleasing device.
 
Sound Quality:
This is arguably the most important part of a headphone review so I will use a combination of numerical data and my own, subjective opinion.
The numbers:
Style - Closed-back circumaural
Transducer type - Planar magnetic
Magnetic structure - Fluxor magnets
Magnet type - Neodymium
Driver Size - 100 mm
Maximum power handling - 15W (for 200ms)
Maximum SPL >130dB 
Frequency response - 10Hz – 50kHz
Total harmonic distortion <0.1% (1KHz, 1mw)
Impedance - 30 ohms
Efficiency - 100dB / 1mW
Optimal power requirement - 200mW – 4W
What these numbers mean is essentially, these headphones deliver a massive range of un-distorted sounds with an essentially flat frequency response.
My opinion/experience: These headphones have phenomenal clarity and precision. I've listened to literally every type of music I can think of that may challenge these headphones and these headphones rise to the challenge. They handle everything from Miles Davis to . Beyond this, I've tried giving the headphones more and more power to see where they start to distort and, well, they don't. I turned the volume until it hurt my ears but the headphones never buzzed or peaked or anything. Needless to say, I've been blown away for the past month.
 
Sound Signature:
Flat. Very flat. The low-end roll-off is lower than I can hear, even at high volumes, and the high-end roll-off is higher than I can hear, and everything in between is essentially flat.
I've been ever so fortunate to get the opportunity to listen to both the LCD-2s and LCD-Xs, and to be honest, it sounds a lot like the sweet spot in between the two. It is flatter and more analytical than the LCD-2s but warmer and richer than the LCD-Xs.
 
Other Notes:
Despite being closed-back headphones, they sound positively open. A huge soundstage with excellent spacing between instruments (you can really easily identify what is making what sound).
 
Overall:
These headphones are easily the best portable planar-magnetics, and I would argue that they may be the best headphones for $1,000 and under (yes that mean I think they're better than the HD700s).

I'm first going to preface this with, this is my first review and so I'd like to apologize for anything I leave out or if I do a poor job.
 
Initial Impression:
At first glance, these appear to be nothing special. They look like cheap plastic earbuds that just so happen to wrap around your ear. If you're looking for bling factor with your audio gear, this lineup is not for you.
 
Build Quality:
As far as I know, they are hand-made in Colorado, made from cold-poured acrylic. This provides a very strong body, ready for daily use and the wear-and-tear that brings. Since it is not a plastic shell that was fused together and rather a single acrylic body, it is quite water resistant too (I accidentally dropped mine in the sink with water running and there were, luckily, no consequences). The wires have held up quite well so far and overall, I've been very satisfied with how they've held together.
 
Sound Quality:
These are incredibly precise. A combination of low distortion and a wide dynamic range allows these to seamlessly transition between stage monitors and personal listening devices. Once a proper seal is made (from the variety of tips provided), it has a surprisingly full sound. The lows are very rich, even punchy at times, though they are never overpowering. The mids are very detailed and full and vocals are very forward. The highs are very precise and, surprisingly, don't hurt your ears, even after long-term listening.
 
Sound Signature:
These IEMs are very neutral, and to those who are used to a more bass-heavy environment, such as Bose, Beats, etc., they will come across as bright.
 
Comfort:
These are really quite comfortable, especially when compared to their Shure competitor. The W20s are incredibly small and they come with 10 different sets of tips (5 foam, 5 silicone) which allows them to comfortably fit in almost any set of ears.
 
Overall:
Over the past year and a bit, I must have put at least 2000+ hours, and I've compared these with the Westone UMPro2, Shure se425, among others, and these came out on top with regards to sound quality, comfort, and build quality.