dustin you should get your distributor to give you an 8mm to review on the EOS-M it'd be interesting to see your comparison and also give mor info to the crop shooters out there.
It really is amazing how good this samyang glass is for what it costs
I had the Samyang 8mm and really liked it but when I got my EF-M 11-22mm I decided the Samyang was so poor in comparison, I sold it.
Of course I lost the novelty factor of 8mm, (which my wife always hated for some reason), but it couldn't hold a candle to the sharpness of the EF-M @ 11mm in comparison and I decided I was not going to be using it much as a consequence, not when I could pack a 11-22mm zoom that was better optically, and less than half the weight and size, and has AF and IS to boot. So off to ebay it went.
Unless you really need 8mm and the fisheye effect, the EF-M 11-22 is a much better buy IMO
Compare these two crops. Now admittedly they were taken on different occasions with different cameras - an EOS M and a EOS 600D, but both very similar 18mps Canon APS-C - Both RAW optimized through LR. But they were both cropped from about the same place - towards the corner - from photos taken in the same place with the same perspective. (and repeated in other images I compared)
for the non-cropped images. IMG_0418 is the Samyang.