I have used these since approximately a year ago, as I bought them after damaging my previous Sennheiser portable PX range headphones by accident.
I would have to agree with bass distortion, but if you are playing your music that loudly, I think you are either hard of hearing or a expecting a little bit much for the price (I paid £50 at the time).
I used them until I got a pair of PC166 Sennheiser USB 'Pro-Gaming' headphones, as they obviously lack a Microphone.
The spatial awareness that these provide (the 215's) in games such as CS:S (a game in which I used to run a clan for two years until heading to Uni) has been excellent.
There are obviously better headphones around for gaming, but these bring a real level of spatial awareness to your gaming whilst looking aesthetically sound.
I have used these at regular Uni LAN parties, and the result has been most rewarding.
Great headphones for the price, and the fact they block out the sound around you means you dont damage your hearing through having to turn up your headset's volume to block out unwanted noise, e.g. I used to use them on the ground floor in Uni housing.
Also nice and comfortable for reasonably long times, with a nice coiled 3m cable which also comes with a spare Jack and nice carrying case.
No real complaints, great quality headphones overall, its what one comes to expect from Sennheiser.
Don't let too many biased reviews put you off, these are worth a look at £50. Especially if you have a soundcard which isn't on-board.