Tony,
I too, was impressed with eye control. Would you mind sharing what firmware version your MK II has? It may be my imagination, but it appears that my eye control has changed since updating to the latest version. Thanks
For some reason the eyeball AF is not good for me. The joystick get me close and then the AF can find the species faster. I don't have pathologic nystigmata, so not sure what the issue is other than perhaps head angles. It did not work for me on the EOS 3 either but that was because the squares were always offset.