This camera's an odd duck. IQ is very good for what it is. The 22mm lens is extremely sharp wide open. Sensor is that old familiar 7D.
The system seems horribly misguided, though. This handles like a consumer camera, but while touch to shoot is cool, it's too slow for most purposes. The lack of an optical finder (or nice EVF) is a deal-killer for "serious" photographers, and the smallness is totally negated by the lack of non-huge lenses available outside the obvious two (and even the 22mm f2 is bigger than one might like for a pocket camera) and the charger's size. I like Canon's gear for its ease of use... not its IQ necessarily, but the colors are always punchy and nice out of the box. Friends make fun of my 5D Mark III and C100 when comparing them with the D800 and Red/BMCC, but then these cameras work so well in the field. But the M is not a well-designed product or at least not thought out that well... or over-thought out. Would rather have an X100s!
Canon's menus are still too complicated. Better than Nikon and Panasonic but awful on most of their products. The pro stuff is best (nothing is useless or wasted), but their high end consumer stuff (5D Mark III, etc.) is full of dumb features and the M has poor ergonomics beyond this, which makes it really awkward. All these companies could learn something from Apple. But the lens is great, and it's a great focal length, and this is a tiny back up, which is cool.
Not sure there will be a follow-up. The images look good. With a few pancake lenses it could be a cool system. I want to put a tilt/shift adapter on it and have a tiny landscape kit. Interesting that the introduce the new 70D AF technology right after they put these on firesale... seems to hint at an update. New firmware is odd for a camera they want to get rid of, too. And yet the lack of availability on the 11-22mm seems to indicate they're trashing the line.
I dig the small lenses on M43. Can sort of see why that's popular now.