AF speed depends on the body. I have that Nikon, and it's a little slow on the Fuji S2 (Nikon N80, basically). Very good on the F100 but noticably quicker yet on the F5. That lens is so sharp you can shave with it... ;)

I also have a Tokina 80-400 that's not a bad lens, but much slower than the Nikon. I've picked up the AFS and AFS-VR, and they're both a little quicker than mine. I bought the non-AFS before the VR was out, and the extra speed of the AFS didn't seem necessary to me.