To me, the main advantage of the VP150 over an M22 is placement and horizontal dispersion. I'd have nowhere logical to put an M22 as a center without turning it on it's side, which makes for odd response differences in different seating positions (left, right, center) and non-ideal left/right response for anything but a fairly distant listening position. One of the things I like about the VP150 is the tweeters on the outside; it doesn't suffer much for those seated far left or far right of center in a large room. Yeah, they lose a lot in other areas, but they can always hear dialogue and the like clearly, it doesn't sound like it's rolled off at the top and it's still perceived as front and center at all times even in a fairly 'live' room such as mine. With my old Polk CS300i, those sitting far left or right suffer more high frequency rolloff from being further off-axis from the single center-mounted tweeter, and more room effect from the center channel than the VP150.
The VP150 will also take more abuse than the M22, but I don't find myself running my center channel at anywhere near its limits. My volume only seems to be really wound up when I'm listening to stereo sources and not actually sitting still in the listening room (cleaning house, for example). The M22 would likely easily get to uncomfortable listening levels in my family room (I'm not sure; I own a pair, but I use them in my home office and have never tried them in the family room... they'll easily go beyond uncomfortable levels in the office, which is more dead in response but much smaller in size).
