I bought a D800 end of April 2013 and it doesn't seem to have any issues. Left AF looks good, no dirt on the sensor yet (800 exposures now), no hourglass and lockup issues either.
For anyone thinking I might be blind to issues or just being a fanboy, please read the D600 thread. I had the sensor dirt issue, I had it bad, and I talked about it.
But the D800 luckily works like such a high-tech piece of kit should - i.e. flawlessly (so far).
I'd like to say that indeed when you read of a lot of people who have the issue, and then you have it too, it requires a bit of discipline to remind yourself that probably the majority of the cameras work well, or else they couldn't be sold anymore, and that you personally just had some bad luck in getting one of the problem-ridden copies. After the issue started with my D600, it kept contaminating the sensor at such a rate that I was most amazed to read from people who said they didn't have any issues, and silently I always wondered whether they had tested it thoroughly, or would maybe still get them later - simply because so many people had the issue, and for example 100% of the cameras in the initial batch of Lensrentals were affected. That sounded like simply all of the D600s had an issue. But apparently some don't, and looking at it soberly, it has to be the majority which doesn't, because otherwise the repair cost would make Nikon poor.
So, I believe that probably the majority of D600 and D800 don't have issues. I did not have so much luck with the D600, I had good luck with the D800 apparently. Mathematically/statistically a well balanced final result
