Pros: Detailed, comfortable, smooth and clear. Free from most outside noise, easy to power, very affordable
Cons: Not end-all be-all of headphones. If these are good, other more expensive models are great.
I had these and used these as my primary method of enjoying music, films and video games for 18 months until I replaced them with a more expensive model of a different brand. Before I owned these, my "greatest headphones" were $40 VOIP headsets. I won't even begin to claim I have golden ears or anything like that, but even a philistine like me could tell that these things were a million miles ahead of any game headset or stock Zune earbuds around. It was so much better than my previous equipment that I actually experienced the "I'm hearing things I never knew existed in my music" effect. This is to be expected from anyone's first pair of good headphones, though.
They sit on my head extremely comfortably. I would notice that I was wearing headphones, of course, but it is the same sort of way that you might notice you are wearing a very familiar hat that you've worn every day for years - you know you're wearing these headphones; it is hard to forget that they are on - but they are not at all obtrusive or unpleasant to wear and you absolutely have no objection to wearing them for an entire day if you have the freedom to just sit down for an entire day. However, with excessive head movement, you can hear the slightly adjustable,swiveling parts of the headphones creaking just a tad, so it's not always a good idea to "rock out" when wearing these. This is the one flaw I can consider when thinking of these headphones - not that I'm sitting here headbanging or anything, but even slight head movements are enough to trip the little creaky noises.
Again, they sound great. I listened to trance (Armin Van Buuren, Tiesto, ATB, etc) other electronic (various Drum & Bass, ambient, Aphex Twin, etc), rock (Pink Floyd, The Cardigans, King Crimson), metal (King Diamond, Dismember, Emperor, Blind Guardian, Death), and a little bit of classical stuff (Mozart, Vivaldi). I am not experienced in a diverse array of headphones, so I don't know much about how other headphones might be more suited for specific genres, but I enjoyed all of this music and more on these headphones.
They don't require much amplification. I say "much," because they sounded kinda "ghostly" when played directly through my first-gen Zune. Bass was very undefined, and things were quiet in strange ways. Plugging into an HT OMEGA PLUS+ sound card worked beautifully, though, and the headphone output of a variety of stereo and A/V receivers worked beautifully, too. A $200 home theater receiver has a good enough headphone jack to make these sound pretty good. I'm sure the cheap dedicated headphone amps you can get work well, too.
These are very affordable at only around $110 or so today. For the price, they are absolutely great. However; they aren't perfect. Other headphones are even clearer, other headphones are even more comfortable, other headphones have crisper vocals and tighter bass. These aren't bad at all and I cannot point you to any obvious flaws in their sound or feel or construction. Just, there are obviously better headphones out there beyond these. I consider these an excellent gateway into audiophilia.