I am thinking of moving UP from a pair of M80v3s to a pair of M100 v4.

Issues:
a. The sound of M100 is not a huge jump UP from M80. A little disappointing given that it is costing me near $1700 to upgrade
b. THe M100 sounds muddled at until 10'. Play it LOUD and go to the next room, it sounds awesome. This is very strange

I am using awesome electronics FLAC files, Logitech Transporter, Ayre K5-xE-MP preamp, and 14B-SST (2008). Self-built cables of course.

CONCLUSIONS: The M100v4 is a tiny hop/step/jump UP from a M80 v3. This is just day #2, so I need to wait and see (NO - I do not believe in break-in). I have seen idiots suggest break-ins for Brystons. Call the factory - the will tell you what to use (example: I blew a fuse in the input soft-start circuits. Bryston recommended $0.25/each fast acting fuses. There exist IDIOTS who pay $75 for a gold/silver fuse - stupid, stupid, stupid.

All opinions are mine.

Sincerely,
BapchaMan - the semiconductor genius