I'm running classic 3 fronts, 3C center, AZ surround + .1 HSU Research VTF 3 Mk3 sub
My room, similar to yours, has vaulted ceiling (fronts is at apex, rears are the short wall). Similar room size or larger, my LR / DR / Kitchen all "in line".
I've had em for a couple of months now (sub for less time) and simply cry when i have to go to bed and turn them off. Music, movies, its all good.
I didn't want the cost nor floorspace demands of the 4's. And I knew the sub was in my plans.
Conformist to a point: Gear is listed in my profile, not in my signature.