getoffb,
My thoughts on the M2i as center channel was in comparison to the vp100, which is a good, albeit typical w-t-w (w=woofer; t=tweeter) center speaker. When placed horizontally, the vp100 exhibits typical lobing effect to the sound that makes the sweet spot for dialog intelligibility rather small in comparison to an M2i placed vertically. The difference becomes more pronounced the wider one's home-theater room is.
While one can place a vp100 vertically in order to get better dispersion of sound ("ooh grandma, what a TALL center speaker you have..."), the tweeter then sits higher from the televsion screen than if positioned horizontally, or if one placed a single M2i upside-down on top of the television. This results is slightly less focus of center channel information, meaning you begin to "hear" the dialog not so much from the actors who are "locked on" the screen, but rather from slightly above them, which can be a little disconcerting.
To me, an inverted M2i, in comparison to the vp100, makes the best trade-off for a small center-channel speaker, providing excellent dispersion while maintaining good focus.
The M2i is quite a versatile little speaker that I think would work equally well as surround speakers as it does as a center speaker, or as mains (in conjunction with a good sub). In fact, five of these little wonders with a good sub would make for one formidable home theater and music system, IMO.
I hope this helps. Good luck!
-alanS.
