The other question is will this update trickle down (up?) to the Rebels and/or other bodies? If the EOS M AF was similar to the T4i Live View AF previously, then it seems that they could also make live view much more usable on the other recent bodies by implementing whatever improvements are included here.
I've read of issues using the 2x III TC with the EOS M/EF Adapter, but I'm having trouble finding details - can someone point me to a link with details? Does it not AF at all, only with certain lenses, or have other issues?