I can also chime in with some detailed impressions of the MD 3.2 and He-400.
*better mids and treble (good with vocals including female vocals...no tizz)
*needs a little more amping than the he-400 to get the most from it (A2 works well, lyr works better, my vintage Pioneer spanks them both)
*bass, more linear. Seems to be very adaptive to the recording. The bass is very natural sounding with jazz and classical, not colored at all. But with bass heavy material, ie new Daft Punk: RAM, the bass will hit hard and rattle your molars.
*Alpha pads are wonderfully luxurious, real leather and angled
*hard to beat this kind of sound at $300
*more overall bass, adds a little coloration to material with less bass. Some will like this as it makes for a more fun listen.
*better soundstage and instrument separation (the MD is closed and will always be trumped by open hp's)
*easy to amp