I do not know much about headphones, but this is a pair that I owned for several years.  I remember that when I first put them on there seemed to be a 'dead air' to them, kind of like listening through plugged ears.  the sound was much better than what I was used to: sony walkmen stock headphones, ipod color stock headphones and what have you.  so from that it was a definite plus.  these were my first over-ear headphones and I will definitely be in the market for that style once again, these left a very good impression on me in that right.
 
one year after I bought them, I noticed a sticky substance coming out from around the ear pads, which I am assuming was glue, I don't really know but it was there.  about two years into using them, the pleather on the outside of the ear pads started to crumble off, leaving me with some sort of pleather dust on my face and ears that was hard to remove...  I enjoyed using them with my ipod at the time, but the cord was very long and had to be stuffed into the pocket, entangling keys and bubblegum and all that stuff...  eventually the ear pads just came off and I still use them but in a very unconventional sense I suppose, using them to transfer personal analog recordings to wav files by attaching them to a usb microphone on full volume... in that sense they work like a charm.
 
unfortunately I don't have much to compare them to, but I think I got the length of use out of them that I expected.  3 stars.  i'm sure there is better out there.