Okay, I've had these for a couple of days now (quick shipping from Bose btw.) so here are my impressions. I've tailored this review for people who want to use these portably.
Equipment Used: To start this off, I listened to these with the Rio Karma, iPod nano, and new iPod shuffle (the player I bought these for.) I personally don't like the Karma's sound too much (too murky / veiled) so I won't go into that.
The nano has a relatively clear sound and the headphones sounded good with it. My mp3s are gained down in volume to 89 decibels and I had to crank it up to about 85% of its maximum volume for a good listen in a quiet environment, so it probably wouldn't be the best player to use.
The shuffle sounds great with them as well, and is way more than powerful enough to drive them to incredibly high volumes. The new shuffle hiss is completely absent. These buds complement the player quite nicely.
Sound: These are characterized by having excellent bass, a nice soundstage, and good detail all around. The sound is quite lush and sounds fairly realistic. Overall, the headphones are a bit on the dark side and I think are relatively coloured (which I actually like.)
The bass itself is really awesome for buds. I've never heard anything else in that headphone category come even close. If you have the Sony EX90 and have it properly seran-wrap modded (you'll know it's well done when the bass starts to thump instead of only growing much more present), then it's that "thump" times about 1.5. With all this though, the bass isn't overbearing, or comes out more in tracks then it should. It just has a good quality sound to it and thumps like a circumaural headphone instead of a bud. You can hear a lot of bass guitar that is normally hard to hear in songs, and I love bass guitar, so I'm very happy.
I don't have much to say on the soundstage since I'm not entirely sure about it yet, but I'd say it's about as much as the Sony D66 Eggos (sorry, not a lot of help to those who haven't heard them), only instead of being only farther to the left or right, they are all around the headphone, back and front, up and down, etc. Somewhat similar to the Audio Technica A900s (though obviously having far less of a soundstage.)
I think they sound good for all types of genres, from rock to jazz/classical to indie to electronic. Some people complained about how they sound bad with alternative rock. I can't see why, unless the recording was really weird or they prefer more sizzling guitars versus the more lush sounds coming from this headphone (get a Grado!)
I'm particularly happy with how this sounds with lo-fi indie music, which I listen to a lot of. It brings the music fairly forward and it becomes more alive. A lot more hidden bass is found as well.
Burn-in: ...Is required. DO NOT judge these based on how they sound at the beginning. Out of all of my headphones, these and the A900s changed the most. Right now, I've put in about 24 hours or so, and the last 8 really seemed to do wonders. The sound used to be pretty good (very dark) but the sound signature was kind of all over the place. Some songs sounded really wonky, like the instruments were put into the wrong place in the mix, not really jiving as a whole. Now, the sound signature has vastly improved and it's pretty controlled. The phones aren't as dark as they used to be (though I don't think anyone would think of these as very bright!)
Isolation/Leakage: Yes, these don't isolate. In fact, don't even try to get a seal out of them because it makes them sound really bad. I find that the medium tips sound best out of all of them. The large seem to fit even better, but I guess the slight seal/isolation that you get from them makes everything sound darker and less detailed.
On the bright side, these things keep the sound in very well. I went for a walk with these today and I could head the louder of the surrounding noise - like cars - but it didn't bother me nearly as much as with normal earbuds, since the sound is contained. For me, they're great walking headphones. And of course, since they don't seal, there's no microphonics.
I haven't asked people to tell me how much sound they leak, but from what I hear, it's little to none, so that's nice too (I often listen to music at the library.)
Useability/build quality: These are quite comfortable indeed, though I wouldn't say that they're the best of all my headphones. They fit in your ear quite securely in a way so that a downward tug on the wire doesn't pull them out. I don't find, unlike other people, that the tips come off very easily. They kind of "snap" into place when you put them on.
The wire is relatively thick and I think can take some abuse. It's very friction happy, which is nice in that I usually wear the wire under my shirt, so its friction prevents it from being dragged down and pulling on the buds while they're in my ears. I usually have to make myself a clip on / safety pin device to attach the wire to my shirt to prevent this discomfort, but I might not need to with these (I'll have to wait and see.)
The buds do not stick out far out of your ears and I can wear a (not too tight) winter toque over them without a problem (yes, winter phones!) And it's kind of a miscellaneous point, but these look very nice and stylish when you're wearing them.
Comparisons: How do these compare sonically with some other headphones?
MX400: Blows them out of the water.
EX90: Beats them handily (same price btw.) When they're modded with seran wrap (and I stress properly modded since, from personal experience, the effect it gives can vary widly), these are a bit better or more in just about every category except isolation - obviously - and soundstage (where it beats them out.)
PX100 (old versions): I think the Bose beat them out as well. Not as much bass as these things, but I think that's to be expected.
A900: Obviously, the A900 win out. But I love both of these phones now.
Overall: Excellent bass, pretty good overall sound, surprisingly decent soundstage, great for portable use. These aren't for people who need isolation or don't have a player strong enough to drive them well them or an amp. Coupled with my shuffle, these are probably now my headphones of choice. I'll edit this post if my opinion changes sometime in the future though.
