Just a quick piece of advice: If you have not installed firmware version 2.0.2
on your Canon EOS M
, move that task up on your to-do list. I'm not ready to say that convetional phase detection AF is dead, but ... the M focuses very noticeably faster with this update – it is a worthwhile install.
If AF speed was holding you back from purchasing an "M", you may want to reconsider that decision.
Get your "M" at: B&H