Recently, I went shopping for a $100 pair of earphones to replace my aging set of UE MetroFi 220 earphones.
 
After much deliberation, I settled on the Sure SE215 series in the clear variant.  They were purchased from Amazon.com directly from Shure.  I am a Prime member, as such I paid the $3.99 and had them sent next-day air.
 
They arrived without incident and well packed in all manner of UPS-proof air based packaging.
 
The actual carton which contained the earphones was relatively standard fare and more or less unmentionable.  Inside the carton was the usual wadge of manuals and warnings printed in every language I've heard of and a few that I haven't.  Also, there was a small bag containing six silicone tips as well as four foam tips (the other two were already on the device) and a cleaning tool.  Finally, there was a zippered pouch with an internal pocket that is just perfect for the bag containing the tips and the tool or in lieu of that a small player such as an iPod nano or shuffle.
 
The first impression on removing the earphones from the package was that they are a quality device.  The cables, which in my case are clear, show off the braided metal sheathing over the signal cables which is interspersed with a copper conductor woven into it.  The plug itself as well as stress reliefs on the cable appear to be much more stout than other offerings, the cable has a very durable look and feel.
 
The cable disconnects appear to be a relatively high grade coaxial-type affair with a signal pin on the cable end sliding into a tube on the headphone end.  Some folks have had some problems with these, but we'll get to that in just a few minutes.  The entire connector assembly was covered in what appears to be a very thin oil, which was removed with a q-tip so as not to present any potential problems.
 
Moving along to the earpieces themselves, the quality craftsmanship shines in their appearance.  The shells are very solid, and inspection of the internal construction reveals meticulously soldered connections as well as a very substantial support for the single dynamic driver.
 
The first listen out of the box revealed good sound quality with a "punchy" quality to the bass, strong definition in the mid frequencies, almost to the point of roughness, and some attenuation in the high registers.  They went for my standard 72 hour burn-in combining equal parts of white, pink and brown noise played at a high listening level.  The burn in period didn't make a huge difference, but there were some minor changes to the sound quality in the form of lesser recession of the high frequencies and a smoothing of definition in the mids without a notable loss in imaging.  Down low, the reproduction gained a bit of force but is still favors mid-bass over sub-bass.
 
In casual listening, they have a very "fun" sound to them.  They are dynamic in their representation and don't tend to get overly sibilent at high listening levels unless the sibilent tendencies are present in the recording.  The tradeoff here is that highs don't have much of any sparkle to them.  That said, I feel they have more than adequate sonic capabilities and qualities.  Listening to them for several hours casually has not been fatiguing or irritating in the least.
 
Moving over to critical listening, their sound tends to accentuate the full mid range with an excellent degree of accuracy across the board.  The high end is rolled off enough to both avoid sibilient harmonics within the listening device itself unless otherwise noted above.  The entire sound envelope of the Shures has a great deal of accuracy with regard to imaging.  The sound stage is both wide and well defined and has more positional accuracy than I would have originally anticipated given the price point.  Isolation while using the foam tips was second to none and provided a very clean sound floor in environs ranging from the office to my quiet living room.  As far as bass reproduction is concerned, the lower frequencies were definitely there in complimentary fashion.  Some feel that these earphones lend themselves to bass heads, however I do not agree with this viewpoint.  While the mid-bass is certainly amazing with a moderate of impact and fantastic texture, I can't describe the sub-bass as anything aside from accurate and complimentary.  To clarify, the entire bass spectrum is represented accurately but without an overpowering amount of presence with regards to the middle qualities.
 
The only issue that I've run into with the device is the oft-posted problem of having one of the earpieces drop connection periodically.  The left ear on my set would cut to silence when turning my head a certain direction or holding the cable at that angle.  I blame the connectors specifically.  To remedy this, I used the tip of a knife* to exert very slight pressure on the pin in the cable-side of the connectors in order to bend it a less-than-readily-visible amount in order to facilitate better connection.  After several tweaks of this type, I am having no more connectivity issues in either ear, and it is smooth sailing.
 
To summarize, I am completely impressed with the devices aural qualities and would definitely buy them again if I needed to.  While they will not please the crowd which demands cymbal sparkle with their rock and roll, and they will not please a true bass-head, I believe that they will please folks who want accuracy, control and an overall fantastic musical reproduction with great isolation.
 
*If you do this modification to your pair, please disconnect them if using a conductive item to tweak the pin to avoid shorting the amp, and be gentle.  To much of a bend and the headphones will not connect properly.  It is better to have to tweak twenty times and do this right than tweak once and have a broken device.
 
List of music auditioned with this device:
Jon Schmidt - All of me (Piano)
Jon Schmidt - Micheal means Mozart (Piano and Cello)
Handel - Assortment of pieces from "Messiah" (Orchestra and Choir)
Mord Fustang - Lick the rainbow (Electro House)
Mord Fustang - Milky Way (Melodic Electro House)
Skrillex - My Name Is Skrillex (Dubstep)
Skrillex - Cat Rats (Dubstep Disco)
Pendulum - The other side (DnB)
Pendulum - Encoder (Vocal Percussive DnB)
 
All tracks were reviewed in all contexts using loss-less files obtained from reputable download sources or created from stamped CD.
 

First off let me preface by stating that I bought these on a whim.  I had read many things about Etymotic's penchant for accurate reproduction.
 
The initial impressions I got from these were a mixed bag.  First off, I love the isolation factor, putting these on in the middle of a crowded communal area was like stepping into a library.  I tried the various silicone pieces which were provided as well as the obnoxious chunks of foam and settled back on the medium sized triple flange which was installed on the unit from the factory.  These tend to sit a little further inside the ear canal, however once they are in I didn't find them to be any more uncomfortable than any other IEM I have used, after a couple of hours it's like they don't exist.
 
Sound quality out of the box was disappointing.  There was a slight hint of bass which seemed to lack much in the way of clarity or substance.  Through the mid and upper ends of the spectrum were just simply "there" along with some harshness and a hint of sibilance.  At one point I wondered if these Etys were defective in some manner, I have read many dozens of reviews and generally Etymotic products are considered to be highly accurate.  Out of the box, I listened for around 30 minutes before packing them up until after burn-in.
 
Burn-in was accomplished over four 24 hour periods, one period each for white, pink and brown noise and the final period being a random selection from my music library.  Sound level was consistent for each test, being set at 0.5db above what I felt was a "loud" listening level.
 
Following the burn in, I wedged them back into my head and went for another listen, and things were very different this time around.  The bass had been cleaned up significantly, and while there wasn't a tremendous amount of it in any regard, that which was there was extremely accurate.  Through the mid-range and high end things were very sharp, crisp and present.  The hint of sibilance which I had detected before break in was gone, as was the harshness.  Imaging had also managed to improve by several orders of magnitude.  Listening to any sort of symphony, orchestra or choir through these devices was truly a treat, you can almost feel the vibrations off the strings.  At some point, I stopped thinking about the devices themselves and simply enjoyed the music.
 
In terms of overall listening experience, I rate them above average for all but the lower frequencies.  I feel that they could have done with more presence to compliment the accuracy.  I would also like to point out that the middle and high frequencies were amazingly revealing of the source.  In my listening, compression artifacts were readily apparent for 128k and 256k mp3.  Artifacts were less present in 320k mp3, however they were still there at various points if one listened closely.  As anticipated, lossless encoding formats presented a truly clear aural picture of what the music was intended to sound like.
 
By the time I pulled them from my ears almost twelve hours after picking them up, I can definitely say that I now know where Etymotic's reputation comes from.  The device which I pulled out of the packaging was not the finished product by any means, however the device that I retrieved from burn-in was the most accurate listening device I have ever had the opportunity to own.
 
Looking at all of the factors, I would recommend these to anyone who prefers the mids and highs to be very strong, present and almost close enough to touch.
 
That said, I would not recommend them to anyone who enjoys a lot of bass with their music, these will almost certainly fail to deliver the volume, bass presence and impact of many other devices available.