I've been using my M for a few weeks now and loving every minute of it!
Just tried the 70-200 II for kicks and felt like the IS isn't working properly for non EF-M lenses sporting IS, based on all the jiggling I was experiencing on the LCD.
When I checked the menu screen, IS was enabled. So I tried disabling IS with the hard switch on the lens istelf, and the screen looks just as unstable as before.
Anyone else noticing this? IS works perfectly and just fine on FF btw...