I am a Mason fan. The newest ones are wonderful, much better crafted than those made in the early 1980s and very much in the spirit of the old Masons that Rachmaninov and Ravel liked so much.
It is a piano with muscle, much more so than Steinway. They need a little love in order for the action to be light and regular enough to play smaller repertoire, but for the likes of Rachmaninov, Prokofiev and Moussorgsky, I think this is the absolute best piano. Bam!
Naturally I like better the larger models, CC and BB. The model A is remarkable for its size (the only 5'8" I tolerate) and AA is much nicer than its size equivalents in either the Steinway and Yamaha lines (which are the most comparable, this is a piano much different than those in the tradition of Bosie, Bluthner or Bechstein).
I would tend to think people would either love them or think they are loud and play like a truck. They suffer from a slightly similar philosophy as Fazioli (highly engineered, powerful ready sound), but without the big endorsements Fazioli has been garnering. On the other hand, an M&H costs half of what a Faz costs and in no scale is it half the piano (in fact, the best M&H I have played was much better than the best Faz I have played, both full grands). A Faz comes much better regulated off the box.