Just to throw a bit of a bug into this mix, I have the M3's with a VP100 mounted to the ceiling in the bedroom. I originally designed the room this way and thought it wouldn't be a problem. The only speaker mounts that I could find that would work, and the only mounts that Axiom themselves recommended were from Omnimount. They only allowed for horizontal placement. There was no mount to be found that would allow vertical placement from the ceiling for the M3's.
As far as the sound goes, it seems to be fine. I just had to be very careful of alignment of the vertical and horizontal plane. As this was for listening in the same position all the time, in bed, it didn't make much of a difference. But had the scenerio been different and if I had wanted to hang the vertically then I would be SOL.
Axiom now offers, they didn't at the time of my purchase, a ceiling bracket that looks a little stouter than the Omnimounts that I ended up with. But they still only work with the bookshelves in a horizontal position. Now if they are reading this, I'd buy 3 in a heart beat if the allowed for Vertical placement of the M3's.....hint hint.
