Read this lengthy incompatibility EF lens list with the EOS M (when the EF adaptor is added) and I am shocked!
http://support-cn.canon-asia.com/contents/CN/ZH/8201705900.html
(in Chinese)
Even the lens is compatible, the AF speed of the new Canon mirrorless is just terribly sloooow, even when it is worked with the latest Canon EF-M STM lenses, which are specifically designed for the EOS M! :-o
http://www.youtube.com/watch?v=-PWAudzi7yw
Oh, what a poor performance it is! Compare that against what the K-01 can do and it is different as day and night!
Furthermore, the K-01 guarantees full compatibility with any of the original Pentax K-mount AF lenses.
After all, the above two good things should be praised! :-)