Ah, the Audio Technica ATH-M50's. These guys have been reviewed to death and praised to high heaven. They were also my first foray into the audiophile category, and overall, I'd say I've been very satisfied with them.
 
The audio quality is amazing for the price, though it excels at nothing in particular; In fact, that seems to be their main goal as monitors. They provide an accurate, relatively 'flat' sound stage and frequency response, and in doing so aren't actually very 'fun' to listen to for extended periods of time. There isn't really much that can be said about them that hasn't already in this respect, and by no means am I knocking them for prioritizing accuracy over fun factor; Quite the opposite, I was delighted when I first received them and was able to identify for the first time many things I'd previously missed in much of the music I listen to. As monitors, they do a superb job, and I've used them for that purpose in the past.
 
There are some issues with build quality and comfort, however. The leatherette ear pads seem to crack over time, and these cracks are very sharp to the touch, which seriously impacts my ability to wear them for extended periods, especially combined with the well-known issue of excessive clamping force. That having been said, the cable is incredibly thick and the gold-plated connector is heavy enough that there's no doubt that it will survive a substantial amount of punishment, with a nice matching spring stress reliever in place of a standard plastic or rubber one.
 
Overall a great value, and a great entry into the audiophile market. They got me hooked for sure.

I got these about a year and a half ago as a Christmas gift, and they've been my companion for some time until the left earpiece one day began outputting a significantly lower sound level than the right. The build quality in general had always worried me, with the drivers rocking a little in their outer casing, the stress relievers at the earpieces actually coming off and sliding down the wire, and other weirdness. However, they did last me for over a year, and Monster's warranty should cover it.
 
With that out of the way, the sound quality is rather excellent for an IEM, as is the isolation. With the proper tips, most outside noise fades away, and you're left with good, tight bass and highly detailed mids and somewhat sharp highs. Overall they tend to particularly excel at faster-paced music, such as rock and metal, which also happen to be what I listen to most often.
 
Comfort-wise, they can be a pain. It seems one of my ears doesn't like having an IEM in, though I had no trouble with the Shure SE-215's I'd been using prior. The plethora of tips that came with them never really seemed to match up with my ear type, and as a result, I'd often have to fidget with them to keep them properly seated. Still, that's more a product of my ears' shape than the IEM's themselves, and Monster did a great job of packing in as many types of tips as possible to work around that. It's worth noting that they are moreso than any other IEM I've used very sensitive to insertion depth, and inserting too deeply or too shallow will negatively affect their performance, from loss of bass (too shallow) to loss of volume or near complete silence (too deep).
 
Overall, they're a pretty good pair of IEM's, though they'd certainly rank lower with me if they didn't have their great warranty.

I really can't say enough about how much these headphones blew me away when I picked them up. My only previous 'high-end' headphone purchase was a pair of Audio Technica ATH-M50's, and while those aren't exactly collecting dust, these have become my go-to pair of headphones.
 
Audio quality is superb. Bass is warm but controlled, and fun to listen to, coupled with very detailed mids and highs. I did at first notice that the treble in certain tracks sounded a little strange, though I've since discovered that the tracks appear to have been mixed that way, since most of the music I listen to doesn't exhibit this phenomenon, and its occurrence did decrease as the headphones were broken in. They function equally well with music, video games and movies/etc, and can just as easily be driven by a computer or amplifier as they can be from a mobile phone (in my case, a Galaxy Nexus). Plus, they tend to isolate very well, and at least in my experience, don't leak sound very much at all, allowing me to crank the volume up in public without being a nuisance.
 
The brown leather and steel design is extremely attractive, and the soft leather earcups are absolutely the most comfortable thing to touch my ears, despite, in my case, not quite achieving the advertised circum-aural fit. They have a very gentle clamping force, though they remain firm while moving around such that I can't shake them off my head if I tried. The simple nature of their construction gives me great confidence in their ability to survive rough handling, and while the detachable cords are somewhat thin, they are sturdy and coated in a sort of rubberized anti-tangle solution that works extremely well to prevent those kinds of stresses. The included mobile cable with inline mic is a nice touch, but the controls unfortunately don't work for Android handsets, relegating that cable more or less permanently to the box (or at least until I get an iOS device).
 
Even though these are marketed as mobile headphones, I find myself reaching for them no matter the occasion, and they never disappoint. Highly recommended.

I picked these up knowing that they wouldn't come close to the quality level of my Sennheiser Momentum headphones, but needing a headset, I figured Razer's flagship would be up to the task. The packaging and control box were very nice, and the speaker pass-through dongle was a great touch. It's also rather comfortable, and the auto-adjusting headband is a pleasure to wear. The microphone stays out of the way, and slides up inside the headphones when not in use That said, though, the good ends there.

In 2.1 stereo mode, the sound is very muffled, with almost no treble to speak of. The bass is muddy, and it really reminds me of the sound you get from PC headsets that cost a quarter of the asking price of the Tiamat. In 7.1 mode, however, this reverses almost completely. Bass is virtually nonexistent even after maxing the "subwoofer" volume, and it turns into a shrill, tinny mess. I did manage to get some bass out of it by using the bass redirection function of my sound card (50Hz seems to be the sweet spot), but even then it was still rather muddy. I tried to use it in a game to see how the positional audio was, but I found myself cringing every time an explosion or some other loud noise happened simply because it was so shrill, and the positional effect was drowned out as a result.

In the end, turning on my sound card's CMSS-3D in headphone mode offered far superior positional audio performance than the Tiamat's 7.1 mode. Lesson learned - You have two ears, and two speakers are far better equipped to handle both quality and surround sound than the multiple drivers inside the Tiamat. With Dolby Headphone or CMSS-3D, a stereo headset offers far better performance.

This headset is quite possibly the least comfortable thing I have yet experienced. The clamping force is extreme, and the supra-aural design means that the earcups are directly pinching the ears while it's worn. No amount of flexing and stretching really helps with this, and while the material the earcups are made of is relatively comfortable in itself, nothing can prevent the serious pinching issues present on these. Working an eight hour shift with these on absolutely destroys my ears to the point where they're tender to even touch at the end of the day. I simply cannot stress enough how uncomfortable these are.
 
As for sound quality, they're... Adequate. They certainly aren't what you would expect coming from Sennheiser, coming in closer to the territory of most Turtle Beach headsets I've listened to; That is to say, they're somewhat tinny and grainy, with muddy bass that doesn't really have any power to speak of. This is acceptable with VoIP and some gaming usage, but they certainly don't excel at music playback.
 
Really, that's about all there is to say about them. They're plastic, they're uncomfortable, and they're merely acceptable in audio quality. At least the (rather thin) cable is long enough to reach behind the computer.

For some time, I'd been looking for a decent all-rounder headset that I could use for both gaming and for work, as my job requires VoIP calls. Previously, I'd been using a Turtle Beach (D)PX21 headset for this, but didn't want to purchase another after its earcup snapped off due to the mediocre performance while playing music. I'd tried and returned the Razer Tiamat 7.1, and most recently been back and forth between the PC 350 and PC 360. After a much longer than necessary deliberation period, I decided to give the 360 a shot. I'm quite pleased to say that the Sennheiser PC 360 did not disappoint.
 
When I first took them out of the box, I'd been listening to my Sennheiser Momentums for the majority of the day. This is something I'd once before with the Razer Tiamat 7.1, and while the results were less than flattering for the Razer headset, the PC 360 pleasantly surprised me. I wasn't exactly expecting miracles from a headset that cost $100 less than my headphones to really stack up at all, but when I fired up some music, I was treated to nice, rich bass and clear mids. Treble, while slightly overstated, doesn't seem quite so shrill as some other headsets I've worn, and honestly seems much closer to the response of my Audio Technica ATH-M50's. This was - finally - pretty much exactly what I was looking for; A good headset that can adapt to music, gaming and VoIP while maintaining a high level of audio quality.
 
For gaming, coupled with my Auzen X-Fi Prelude's CMSS-3D, I found positionality to be excellent. In the test loop, I could visualize the sound tracing its way around my head, and when I fired up World of Tanks and Team Fortress 2, the results were even more spectacular. It's unfortunate that CMSS-3D tends to emphasize treble so much on a headset that already has strong highs, but a mild EQ adjustment keeps it from being overbearing.
 
Comfort-wise and construction-wise, the headset is a mixed bag. On the one hand, the massive velvet earcups and their padding is extremely comfortable to wear and wraps completely around the ear, but on the other hand, the clamping force is a little extreme for my head. I've flexed it somewhat, but the plastic construction makes me nervous, especially when it creaks and even sometimes pops out of place from the pressure. I've heard very good things about Sennheiser's warranty (which I've thus far never had to utilize), so I'm hoping that if anything does happen, they'll take care of it. The generously lengthy cable, at least, is fairly thick and well-shielded, and has a similar semi-rubberized anti-tangle coat to the Sennheiser Momentums. It feels absolutely solid, and the stress reliever going into the left earcup is quite firm.
 
As for the other features, the in-line volume control on the right earcup is handy, though it doesn't go 'all the way' down; It seems to cap the lowest volume to roughly half of the input volume, which is fine but unexpected based on most inline volume controls I've used in the past. The microphone is something that most reviewers comment as being ingenius, and it is. Having handled the PC 330 headset before, this works pretty much the same way. However, when moving the microphone past the mute threshold, the traverse is much smoother with a soft 'click', versus the heavy 'snap' on the PC 330's.
 
Overall, an awesome all-rounder, soundly beating out the Razer series in audio quality by a very wide margin.