I have both M2s and M3s, and there is no comparison, IMHO. The M3 is an astonishingly satisfying speaker, for music or as part of an HT system.
The M2 has received rave reviews, but to my ears, sounds flat and lifeless in comparison to the M3s.
My M2s are back in bubble wrap stashed atop my garage fridge.
I have a system in every room without a toilet:
Big - Thiel CS3.6s, QS8s, Michaura M55s (M22 like)in the back position, modded Frankencenterspeaker, SVS 20-39;
Office - Michaura M665s (M60 like), VP150, Mission DS77 surrounds, Dahlquist 1500 subwoofer;
Dining Room - Michaura M55s, (sometimes M3s) Velodyne 10" (2 channel)
Living Room - Dahlquist DQM905s, supertweeters, Titanic Vance Dickerson sub;
Garage - M22s, modified Kenwood SW300 subwoofer with replaced Dayton 12" driver.
No room for the M2s in any of these systems.
