The EOS M takes great shots and I often put the side by side in a gallery with MKIii photos... but the form factor is totally different.
Forget about seeing the screen in bright sun. No viewfinder also means less stable since it's not sitting against your head for a point of contact. Focus is amazingly slow and manual focus is essentially useless. Still, a really nice compact high quality camera with great tone and full manual operation. No port for an intervalometer, but does have mic in and phones out. Has a hot shoe too.
I take a fair bit if high def video with it and it is so light that I prefer it to a shoulder rig/5d on casual shoots. You can sorta pull focus with it too once you practice a bit with the touch focus.
I have both the pancake lense and the 18-55 is. I often toss on the adapter and use L glass.
You can get the M for under $300 right now and I think that makes it one of the best deals out there.