So far the only problems I have with them is the fit and the warmth. The way the headband works they feel really light, like they're going to fall off, but I can shake my head around a fair bit and they don't move.
@lestatar: Satch is amazing. I'm getting back into him. I liked him a lot back in highschool when I was playing guitar a bit, but I dug through some of my old cds when I was re-ripping my collection and remembered how great he was. I'm ashamed to say I never purchased crystal planet, but its on my list to buy next time I'm ordering something. I saw he has a new album coming out, I'll check out the single, thanks for the tip.
@skip252: I've only tried them through the headphone out my computer so far, but I can try them on my players soon. I have a rockboxed 4G ipod classic and a jailbroken touch. From my understanding they should need an amp volume wise. My computer puts out plenty of volume for them I'm at about 1/3 volume on my desktop and it's enough to cover up any external noise.