I'm very happy with the M22s as surrounds. I originally bought them to serve as mains and used them for about a year as mains (I used to change speakers a lot...upgradeitis, you know). IMO, the M22s are excellent speakers and compare favorably to speakers costing many times more.
I've heard the QS8 in action and for movies they do a little better job at creating the illusion of space and ambiance than the M22s. But if I had a choice, I would use the QS8s for movies and the M22s for multi-channel music. To my ears, the QS8 tended to sound a little "phasy" with multi-channel music but not unbearably so.
My surrounds are positioned slightly behind the main listening position about 6' on the left and about <7' on the right. I have them positioned above ear level so that they are not easily localized and to give the illusion of being more omni-directional. I'm quite happy with this setup.
