I just picked up a D800E over a D600 due to several reasons. First it was the flash sync was not up to 1/250.
Second was the bracketing. I am an Architectural photographer and I bracket 5 shots. It makes it much easier to dial 2 over and 2 under and just click away. thus avoiding me messing up. I want to focus on the photo I am taking, and not worry about spinning dials.
Lastly it give me the ability to produce large prints for my clients.