In reply to:

Additionally, in my view(I haven't heard the VP150)a vertical center speaker has a wider and smoother horizontal dispersion and should be preferred where possible.

Mark the calendar - I'm disagreeing with JohnK.

I recently tried the M22 versus the VP150 as a centre, and in my testing (in my room with my gear, YMMV) I found a vertical bookshelf to present a much narrower soundfield than the VP150. You get "off axis" in a much closer distance than with a horizontal centre.

Bren R.