Hi
NWDIVER
I posted a question regarding the 80-400VR a few weeks ago,
as many reviews of this lens all complain about slow focusing...
So i popped the question on the list, and made a comparison to the 60mm Micro's focusing as its the same system ( driven by the motor in camera and not lens)
the response was indeed positive, with my likeness being confirmed.
I still have to make my choice of what to buy as i'm going to borneo next year and wanted a lens to deal with the Orangutans.
My Short list was
Nik 80-400VR
Sig 80-400 OS
Sig 100-300 F4 with 1.4x TC
I recently purchased a 80-400 OS Sigma.
Very nice well built extremely rugged and exceptional tripod mount should you require it.
HOWEVER its heavy.. but it is 80-400 Glass.
Now I had an issue with the lens on my D70
It was Locking out whilst focusing , i had to resort to turning my camera off to regain control.
It was also making some real strange grinding noise when the OS was suppose to work..
I ended up taking the lens back and getting a refund, ...
Although images that came from it were excellent and sharp
I'm now going to try another 80-400 os as i think i maybe had a bad lens.
If its the same, then its the 80-400VR for me i think. 
regards
craig
take a look at www.fredmiranda.com for reviews