Anyone think it would be stupid going from hd 600's to these? I got my hd 600's for $300 and will get the ma900's for ~$200. I really enjoy the 600's, but I don't find them as comfortable as many have said. Also my creative z can't power them well enough, as they sounded far better on a schiit magni I tested. Another needed purchase just further diminishes the value of the them.
Not necessarily. Much of the appeal of the MA900, at least for me, is that you DON'T need an expensive amp backing it for it to sound good or even function at all.
Comfort is also another major factor; sound quality means absolutely nothing if you can't stand to wear it for extended periods of time.