Hi Axel,
The VP100 and VP150 are excellent speakers. Perhaps the key point is that they are *designed* for the centre channel. This means, among other things, that the dispersion patterns are intentionally designed for the speaker to be placed on its side rather than upright.
Lots of folks around here will recommend that you do as you suggest - get three M22's across the front. That would be a wonderful solution, but ONLY if you can place the centre channel vertically (which is a WAF-killer for me personally).
The other thing that sometimes comes into play (and this is another one of my personal problems) is that the centre channels are NOT ported designs. This is very helpful when the "best" placement for the speaker involves less than optimal acoustic compromises like home theatre cabinetry.
I think you'd find the timbre matching of the VP series to be more than acceptable. The VP150 is universally loved by Axiomites.
