I thought I might mention that my first D800 went back to Nikon for AF tweaking in September 2011. I still purchased a second D800 body (in September 2012) and it is flawless. There's a big margin in the serial numbers. I would just like you to know that NPS Australia (and particularly their GM, Robert Lindsay) were fantastic. They/he asked that I package the body and ALL of lenses I use on that body, not just the new ones (so this includes lenses I have owned for thirty or more years) and they/he organised a courier collection that afternoon. That was a Wednesday and all my gear was returned on the following Monday, everything cleaned (my old lenses looked brand new, inside and out) and every lens checked on that body. Nikon did indeed make adjustments to the AF sensor and there are no AF Fine Tune changes on the body. All this and no charge, not even for the freight either way... and that was a huge 15kg parcel!
In a world of bad news and people complaining about Nikon service, I feel I have to say something about my positive experience. It's not the first time Robert Lindsay has helped me and I'm sure it's not the last. He is also notable for responding to emails at all hours... I hope he doesn't burn out! (maz)