BigNorm,
I am probably the only person here that owns Polks and M22s. I have RTi8 fronts, CSi5 center, and FXi3 surrounds with a Velodyne CHT12 sub. I get the impression that the RTi8s and FXi3s are just new (and improved?) versions of your fronts and surrounds. My CSi5 is both newer and an upgrade from your center. I use my M22s for a stereo in a different room with a Velodyne CHT8 sub. I think the RTi8s and the M22s have a very similar sound (in terms of detail) with the Polks sounding a little more "forward" which I like - but I also like the sound of Klipsch speakers (the Polks are not nearly as forward as Klipsch, though). I think of the M22s as a great $400 bookshelf speaker - but I think it is unfair to compare it to a tower like the RTi8 because it can't compete at the low end with a good tower speaker (that costs $800/pair). So overall, I think that Axiom and Polk both give good value for their money - with Axiom probably doing better in that regard because they sell direct. I think the fair comparison is the RTi8 to the M60 - and I suspect that the M60 is better. So, now that I have been really longwinded - I would not consider the M22 a significant upgrade from what you have unless you have gotten to really not like the sound of your current system.
On the surround front however,....I'm not impressed with my FXi3s and I suspect that the QS4s and 8s are significantly better speakers. So, what I would do if I were you is to get the QS8s and try them with your current system and if you really like them consider an Axiom center. Then if the RTi70s don't work well with the rest of the Axiom stuff you might get Axiom fronts. Do you have a sub? If you don't you will need towers up front - or you can get a sub with the M22s.
