I used to own a pair of M12 but gave them to my sister recently. Many people comment that the M15 which is the floor stand version of the M12 sounds worse than it's sibling stand mount.
I have not heard the Quad but the Epos as point out by others that they are very revealing and therefore a bit fussy with upstream equipment, but they are always a pleasure to listen to.
I tried the M12 with the Nad C370 and found the bass can be boomy even in larger than average room.
Wes Phillips did do a review of the M15 and he said the Arcam 85A is a good match.
I have not heard the Quad but the Epos as point out by others that they are very revealing and therefore a bit fussy with upstream equipment, but they are always a pleasure to listen to.
I tried the M12 with the Nad C370 and found the bass can be boomy even in larger than average room.
Wes Phillips did do a review of the M15 and he said the Arcam 85A is a good match.