From a very small sample space, people with lots of distance between the back of their seating position and the rear surrounds seem to be very happy with direct (eg. W22) rear surrounds; people who have the rears closer seem to prefer QS8s because the sound gets diffused a bit more and so the surround effects are more "natural"...

... if that helps.

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8