I recently choose the M60's over the B&W 683's. I personally liked the 683's better than the 703's. I did not listen to any of the 800 series (why ruin my expectations when I can't afford them anyway). For me, the choice was made because of the price. I really thought the 683's had an edge over the M60's, but not a $1000 edge. I REALLY liked the surrounds that B&W had to offer (DS3's). I was not sure how the QS8's would work. Since I've had them now for a week or so, I can say I'm impressed.

Dave
Audyssey Setup Guide