Very much enjoyed the review - and the pics of the M on the 600.
I find that when I use the 70-200 on the T3i I hold the lens more than I hold the camera - very light touch on the camera, even when adjusting settings, etc. Clearly would do the same w/ the M.
Looking at the ISO crops of the 18-55 EF-M versus the 18-55 EF-S it appears the M version has a sharper image profile mid frame and out (comparing the 60d to the M).
Once the Magic Lantern guys get focus peaking on the M, manual focus may be faster and fast enough for all those not quite so fast action shots.
As fun as it looks, I don't think anyone is going to using the M on longer focal length lenses as their primary configuration, I think targeted at the more casual & indoor environments this could indeed be a great jacket pocket/purse camera. Capable of great art, etc, just not it's primary mission.
The 22 f2 pancake actually looks like a pretty darn good lens at f2 compared to either the 20 or 24 EF.
As a second crop body this could compete very much w/ the the Rebel line up for those who have a primary FF body. hmmmm