Yesterday I took my 60D with the 40mm pancake on our daily walk. Compared to similar pictures taken with the EOS-M and the 22mm, it feels like the M/22mm combo definitely has an IQ edge. I like the sharpness and the color saturation on the 22mm better.
Also, despite the relatively light setup of the 60D with the pancake, it felt like I was lugging around a brick after getting so used to the EOS M.
Another thing I noticed was that I had not missed the viewfinder as much as I thought I would. This is different from my past forays into mirrorless cameras, if the camera did not have a viewfinder I found that to be a serious negative. Not so with the EOS M, I think it's because I find the LCD to be superior to the mirrorless cameras I've tried in the past, and also the super small size makes it feel a bit more natural to shoot it like a true point and shoot camera. I've had ergonomic issues with some slightly larger mirrorless cameras (especially when paired with larger lenses) where I felt I was trying to hold the camera like a DSLR but did not have a viewfinder, so it felt awkward.