Any time you can use 3 identical speakers up front will give you the best, seemless sound. There are design compromises in a horizontal centre simply because the vast majority of users must place it below or above the screen. This is true for all manufactures of horizontal centres, not just Axiom. The VP180 and 160 are excellent centres but if you are able to use a third M80, I'd definitely go that route.

Half of communication is listening. You can't listen with your mouth.