I've actually heard the AE2s (I think), they have a nice warm and laid back sound, right? The Momentums are similar, only better, but they do have more bass, which can feel overwhelming. Neither of them are good choices for metal because they are slow and don't have raised treble for guitar riffs, and metal doesn't really go well with a lot of (slow) bass either.
I also noticed a lack of upper mids/lower treble on the Momentums, that you can see in GoldenEars' graph. It's not noticeable in pop or rock music, but it is in symphonic music (if you know what to expect). I didn't try metal with them, so I don't know if this will be an issue and they're still better than the AE2s in this regard, obviously.
They do have great mids, which IMO metal kind of needs to separate the vocals from the rest of the wall of instrumentals that the genre often has.
Overall, I do think the Momentums are the best portable headphones out there, but they still have too many flaws to be worth $300, IMO. Not counting Bose or Beats, of course.
Thing is, there isn't a better alternative. Portable, closed, for metal I'd say HD25 but that one's ruled out here... If you are a lucky person, maybe the DT1350, don't know how they are confort wise, though.
Edited by Wildstar - 6/15/13 at 11:29am