Second shoot today, and it went much better. Paid more attention to the actual numbers than the tactile feedback of the mirror slap, and made sure I was in AF-C. Had a little more ambient light this time (although was still overcast and under cover) so the eye focus worked beautifully on both my 24-70 f/2.8 and 100 f/2.0 More things I liked: The EVF is a real winner. Not only does it allow you to zoom all the way into the image, (unlike the 5D-II that only zooms into the thumbnail) it allows you to give the camera to the model where they can have a really good look at the results rather than chimping off a reflective screen in the sun. Things I don't like: The refresh rate of the EVF. Not quite real time for fast moving subjects, I am not sure how the sports shooters would go with it. But in my usage, the benefits of the EVF far outweigh this issue. Hopefully I will be able to find some locals with a 5D-IV and EOS-M to compare them head to head.