Thanks for the thoughts. I'm still a couple weeks away (hopefully) from moving my audio gear from my family room into the theater. I think I'm probably going to go for it as I've never been completely happy with the VP150 (more for music than movies), and I've always thought that it might be because the M80's just sound so good it can't quite keep up. Or maybe it's just me. Anyway, it might be worth a try with the 30 day return policy.
Your thoughts echo mine. I can't stand horizontal center speakers for music however for movies I don’t mind quite as much though after getting use to having a vertical center I don’t like to switch back. If you’re ordering with the thought of returning it if the difference isn’t big significant then you might consider ordering an M22 at the same time. If you cross all of your front speakers over at 80Hz the M22 will sound very similar to your M80s. I prefer my front speakers crossed at 40Hz so I stuck with the M80 center.