So after a week or two and many hours of listening, I feel that my initial assessment of the MA 900 may have been a little off base (or completely off base?). Really enjoying the headphones now and feel that any unpleasant brightness I heard before was my brain getting used to headphones again. The MA 900's seem very laid back and seem to pair well with tube amps, which is a plus for me because I don't own anything else.
Also, it may not need to be repeated, but man these are comfortable. My only complaint at this time is that the cable isn't hot swap, but that is minor.
A pretty good way to start my second journey into headphones.