Went to a very nice high-end shop in West Palm (that I have never been to) with Alan to hear the M-51. Very accomodating guy shot the breeze with us for almost two hours and played the DAC in two different systems, neither of which was enough "my cup of tea" that I can actually tell you with any certainy what the M-51 sounds like. It does seem promising, though. I bought a QRP pressing of a Dead record.
Then we went back to Alan's and listened to what that same music is supposed to sound like - or at least what both of us think it's supposed to sound like - on Alan's big system.
Then I installed my two new Squeezebox Touches.
All in all a really good day.