They are somewhat comfortable, I'll give them that. But the mids were very thin. I listened to an Earth Wind and Fire song (September, if you're curious) on the iPod Touch I used them on (this was at the Apple Store) and the vocals were very lifeless. There was a huge lack of any kind of warmth, and I just wasn't "feeling" the music. I admit, this is the only song I tried, but if you've heard it you'll know that after hearing how it sounded on them, I didn't need to hear any other songs.
Despite that it really lacks in sound quality, the noise canceling was pretty good. The apple store was busy today and therefore, pretty noisy. Even before I put on the music, there was a pretty noticeable amount of noise reduction.
So in conclusion, don't buy these. Don't let your friends buy these. These are the first Monster product I've dealt with and even though I know of their reputation among the high end crowd, I was going to remain unbiased until I had a reason to like or dislike them. Because of these headphones, I don't think I'll be buying any Monster products in a good while. I really can't believe that they are charging $350 for these, either. Not even Bose rips their customers off that much. At least Bose makes good headphones. Aside from costing extreme amounts of money, Bose's at least have pretty good sound quality and are very comfortable (much more than the Beats). But seriously, my V-Moda Vibes ($100) sound worlds better than the Beats, and they fit in my pocket.