Dave, keep in mind that some people choose a bookshelf(s) due to space restrictions over the VP100 and VP150. Some use a bookshelf below and one above their screens, but in many cases(not all) it is about space restrictions: Alan at Axiom, in fact uses this setup in his NY apt. I asked a similar question a few weeks ago on the forums (M22s vs VP150 as centre) and for the most part, I think more by default, because many haven't tried using bookshelfs for centres, the choice was the VP150 but there are several members who liked/preferred the bookshelf setup too. If you're seriously considering the M2 as a centre, I would contact Alan by pm/email and get his input. \:\)

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