I purchased an EOS M with the 18-55mm Kit lens, then bought this as a lightweight carry around. It produces nice sharp images, even wide open (and it is fast at 2.0) with nice Bokeh. Auto-focus, for me has been fine. I've seen some reviews saying the auto focus is unusable but I have had no problems-I'm not going to pretend its hugely quick and I don't shoot sports, but its fine. I guess it depends on your expectations, I am getting great images and that's what matters.
This is the lens I keep on the camera all of the time now, don't get me wrong the 18-55mm is a great kit lens, but the 2.0 maximum aperture just makes this a really versatile partner for me. I've also bought a Lowepro Dashpoint 20 bag which fits the EOS M and 22mm Lens perfectly, and makes this a truly portable pairing as a compact walk around camera. My cumbersome DSLR takes great pictures, but so does this-the difference is I can take this combo everywhere with me.