I had a very pleasant experience with Nikon US service. The AF/M switch on my two and a half year old D800 broke while I was in China and I waited until I returned to the US to get it fixed. I live in LA so I dropped the camera off at the service center on a Monday and they sent me the estimate for the repair _that day_ (B2). They said it would be a 7-10 days to fix it, but they called on Thursday and told me it was done, I picked it up on Friday.
As far as the initial failure goes I'm not exactly nice to my camera. It’s been through several rainstorms (and a unexpected spring snowstorm in Yosemite) that have required it to sit all night by the heater so as to have the buttons work again... But the camera torment have yielded some nice shots. (cd)