[gyoung]

So many of these 'problems' stem from incorrect test methodology, testing in a way that doesn't take into account the way the af systems work.  My D7000 showed inaccurate focussing with af when I got it with four Nikon af lenses, but is fine now that its been adjusted by Nikon, with these lenses and a couple of Tokina af lenses, as well as manual focus with confirmation.

I have just bought a Tamron 17-50 /2.8, following a close read of tests here and elsewhere, it seems ok so far, I will look closer!