I've had these for about seven years now, using them for many applications, including use with an MP3 player, computer gaming, and home recording (with a Boss digital 8/64 track). The sound quality is certainly a step up from ear buds, and good in this price range.
The bass is quite overpowering at times, as is the treble, leaving the mids muddied and confused when listening to music at high volumes. A little play with your EQ controls should go some way to resolve this, but its one of those things - you get what you pay for.
The construction is solid enough (again for the price range) but don't expect the plastic brackets holding the cups in place to last forever. Mine snapped on the left side, and is now taped together, but doesn't stop them working as they always have. The headband is also plastic, but a lot more sturdy. Mine get thrown in my bag when I go to work, and have survived almost intact.
The cable is very long (3 metres), which can be a pain - they're certainly not any use for portable use. For that try some of the lower range MDR-V150 (which I also have and are almost as good as these, with a shorter cable). The end is a 1/8inch standard plug, with a 1/4 inch adapter that screws in place - meaning it effectively becomes a part of the cable, and won't easily be lost.
All in all these are a good set of cans for the price - at their best with a portable player that doesn't stress them too much. A computer or home amplifier will push them a bit too hard and expose the flaws in their sound reproduction.
I'd like to recommend these, but I'm not sure who to. For use when travelling the cord is too long to be practical. For home use you'd be better off buying something a little more expensive but a lot more suited to a higher powered situation.