Well I can´t tell much about B&W and M3´s since I only have M22´s, QS8´s and just got my KEF Q300 yesterday. My initial considerations were B&W 685 and the M3´s for a 2.0 system. AFter reading some reviews online heard good stuff about the KEF Q300 having a slight better sound than the B&W. The thing is that the Q300 is not as that appealing to the eyes as the B&W you are considering. Looking at the pictures thought they weren´t really nice. After getting them on my home and setting up on the stands, which receive them for free (B&W STAV24), they really look nice. The sound is very similar to the M22´s ( just listened to 1 day, so can´t give you much info), but they have more bass. Taking in consideration you will be getting a sub if your speakers lack a bit of bass is not a issue. For 2 channel mode I do believe that the M22´s lack a bit of soundstage. If I were you I would be then considering getting the floorstanders. Well, this is my opinion only. Pretty sure other people will have different opinions and may give you a better advice though.
