Great pair of headphones if your on a budget. Sennheiser are known for their quality built headphones and these are no exception.
I originall bought them to plug into my amp and listen to my electric guitar "quietly". They performed pretty well at this and handled the low basses without distorting. The only slight downside is that they weren't very loud. I'm not one for really loud headphones, but when these reach a certain threshold of volume they start to distort a bit. Under most circumstances this is fine, but sometimes I find myself needing a touch more volume out of these.
I also use them now for listening to music and playing games on my PC. The headphones sound absolutely great for both music and gaming and the sound quality is really crisp.
The only difference you'l notice between these and an expensive pair of Sennheiser headphones is the range that they have. For a budget pair of headphones they handle low bass quite well, but it loses a lot of its depth the lower you go. Unless you are an audiophile you really won't find this an issue. I know I don't and I don't plan on buying another pair of headphones for a while.
These things are built to last, on numerous occasions I have stepped on them, kicked them, dropped them and put them through quite a lot of abuse. They stood up to all the wear and still are in great condition.
These headphones are also fairly comfy to wear, for any shape of head. However I have used headphones that are a lot more comfortable than these. This isn't really an issue unless you plan on using them for long periods of time.
In short. A great pair of headphones from a respected manufcaturer and great value for money.