I did some brief comparison of MA-900, HE-400, Mad Dog and Alpha Dog.
The MA-900 continues to excel in its presentation of the space in which instruments exist. It has a three-dimensional spatial presentation that gives aspects of a recording not found in any other headphones that I have heard (although I expect that the HD-800 do this also).
With a good amp and the earlier mentioned headband mod, the bass on the MA-900 is surpringly good in quality and level.
I think it is the best $180 you can spend on headphones, and the best headphones in hot weather.
(Of course, the Mad Dog and the Alpha Dog both have excellent isolation. The Mad Dog is excellent for rock and EDM, and good on all genres. The Alpha Dog is exceptional for classical and other acoustic music - the instrumental timbre and detail are excellent.)