The width of soundtage stood out on all the material I listened to. I don't know that I picked up on the depth so much.
The two things I think could improve on the M3 are the mid bass hump and a bit of a lack of clarity on the upper end. Oh, wait, you did that already and called it the M22.
I was also back and forth on the female vocals. I found the B&W more natural on some passages and the M3s on others.
As a first time buy its a no brainer for the M3. As an upgrade from the B&W its a latteral move.
Edit: its funny, when I first filled out the blind listening form I wasn't so sure I ageed with my conclusion that what turned out to be the the M3 was better, but now I remember the better soundstage much more than any other difference.
