I have owned the M22's (along with VP150 and QS8's, plus sub) for about a year. I have loved them from day one. About a month ago, I moved, and purchased a pair of M3's for my bedroom. When I got them, they went straight into the bedroom--I never bothered to compare them to the M22's, as I didn't think there would be an issue of which I would prefer for my main system. Well, maybe as a result of that speaker face-off where the M22's did not fare that well, I wondered if maybe I should be using the "warmer" M3 for my main system. So, last night, I finally brought my M3's into my living room and did a comparison with the M22's.
Briefly, this was not a blind test (I couldn't bear to ask my wife to help in another speaker comparison), but it turned out it didn't really need to be blind--the sound was different enough that I would have known which was which. And, obviously there is no potential brand bias here, as they were both Axioms. Whichever one I preferred would stay in the living room, period. The other one would go in the bedroom.
To cut to the chase, in my opinion, the M22's were clearly the better speaker. Despite some of the descriptions from the face-off of metallic and tinny, the M22's to me were still clearly not metallic or tinny. A tad bright, maybe. But, smooth, open and airy, not metallic.
The M3's are excellent speakers as well. And standing on their own, they are amazing for the price. But, for example, listening to James Taylor Hourglass, the M3's had a bit of a warmer sound, and a bit more bass (I had to turn my sub down to match up with the M3's), but only in comparison to the M22's, James Taylor's voice sounded a bit recessed. With the M22's, James Taylor was in my living room. Very smooth sound, and open soundstage. And, any benefits from the M3's better bass are meaningless since my sub fills in whatever bass I don't get from the M22's. The distinctions between the two were apparent with more CD's, jazz, classical, hip-hop, whatever.
So, bottom line, as many have said before, both the M3's and M22's are outstanding speakers for the price. If you like a bit more laid back sound, the M3's would be a fine choice. If you want a more forward sound, where you truly feel like the performers are in your living room, the M22's are a fine choice.