sorry not sure about the C-AF comparison between the EM5 and the EM5ii, but I have tested the EM1 and the E-M5ii in the camera shop and the difference is quite substantial. While the E-M5ii would take half a second to acquire lock when the subject focused was moved closer or further, the E-M1 would be literally tracking the subject real time and did not miss focus at all.
The CAF on the E-M1 firmware 3.0 has improved the camera to a point where C-AF can be used for S-AF type of work if needed. The speed at which the lens moves into focus is almost the same as using a proper DSLR phase sensor. There is no hesitation, no racking back and forth. Literally the moment you half press the shutter, the lens knows exactly where to go and moves in the correct direction. There is no overshooting the focused subject either, which makes for very positive responsive AF experience.