Lol this thread just makes me laugh.
I realise that there might be a difference between what I call a good shot, and what you guys call a good shot. I shoot kids like I shoot wedding or events, which means anything that fails to capture that exact moment where emotions running high is considered a failure. There's a 1 to 1.5s window to frame the shot, focus, and capture the laughter or other emotions. There's no need to track them. I take about 100 of such candids in a 3 hour wedding dinner or other events.
That said, I hardly doubt the d800 can nail the shots I want. Maybe a few times. Maybe slightly more than a few times. But never at the amount that canon's af system can provide for me.