OK so I've spent some time going through the menus and setting the camera up, it still needs a bit of tweaking but I'll do that as I get using it and see what needs to go where. I'm not sure what a number of the menu items are so I need to investigate
Overall I'm pretty impressed, the ergonomics are actually better than I thought they were going to be. I'm not blown away by AF acquisition speed tbh, but then I might not have been using the best lenses to test this (35mm f2.8 and Samyang 45mm f1.8). I've very impressed with tracking and eye AF, as you've all said it just sticks.
I do have one pretty big disappointment though, and that's the LCD and EVF. When you are half pressing the shutter to AF you get some subtle kind of pixelating and then some not so subtle rainbow effects with bright light as in this video I've posted. Surely this can't be normal can it on such a high end camera? What's weird is the effect is vastly reduced (although still there a little) when you use the silent/electronic shutter, I can't explain that. It makes no difference if I choose high screen quality or alter the refresh rate. Any thoughts?
Watch the rainbow artefacts when the AF box lights green.
View: https://www.youtube.com/watch?v=9wZ7NjertXc&feature=youtu.be
EDIT: I think I may have found the issue, looking online anti flicker causes some weird issues like this. I've turned it off and it's better as far as the pixelating's concerned, but I'll try tomorrow with bright light as it's dark now.