(unknown member): Great! As one should expect from Canon, this is a solid camera that doesn't tread heavily on the G1 X nor the DSLR lines. It fills in a gap that people have been wanting filled for a long time and allows you to use the rest of your Canon kit. Canon knows they've got most of their bases covered and they have no reason to come up with gimmicks that they would pass off as "innovations". This is basically a small 650D, probably produces the same image quality, and it will be interesting to see the new line of lenses in action.
I'm a sony nex 5n owner and love that camera. The only turn down for me is that I can't use my canon EF glass on it. It doesn't have a hot shoe mount either. So to me if the EOS-M has the image quality of the NEX 5 its a no brainer for me to switch. I'll be able to use all my Canon EF glass on it with the adapter, I will also be able to use wireless triggers with it since it has a hot shoe flash. Then only use the 22mm F2 lens when I want to travel light and use the EF lenses and wireless triggers when I want to be creative with this little camera. If you are Sony user and have tons of Sony lenses the NEX makes more sense since you can use sony lenses on the NEX with the adapter not counting manual lenses I'm talking about Autofocus here. But if you are like me that most of my gear is Canon. Canon is the best mirror less solution for me at least for now.