i dont agree that the d800 is a disapointment for being a 36mp camera and at the price point it comes in at. i do agree that the d4 is rather disapointing because of the iso not being much better then the d3s, and the d800 isnt much different as far as iso in the usable range under 6400 once you resize the images to similar sizes.
IMO, if the d800 would have been a 12 or 14mp camera that they dramatically increased iso over the d700 then they would would have a lot more people upgrading. i actually wouldnt mind trying the d700 to compare to the d800.
the only real downside to the d800 is the 4 FPS, which i really dont care about, i dont shoot much sports, but i have shots some wildlife, and its just fine. but i will say a nikon v1 with FT converter is a 2.7 crop and will shoot up to 60 FPS, so if i ever need insane speed i can just use that. i also have to say although, 36mp files are huge and rarely needed. i still love it when i need to crop a bit, but still print rather large photos. also i love being able to run the d800 in DX crop mode, to get 16mp files make my telephoto lens get 1.5x closer, not have to crop in post, go up to 5fps and not have to crop or deal with large files
in reality guys, cameras are just about how you use them. there where pros back 10 years ago when top of the line dslrs had less technology then an entry level dslr. buy a camera that fits your needs best.
IMO there is not much of a difference in IQ or ISO between the d4 and d800, maybe thats why people are saying they are a disapointment. because 36mp is just too much, and the d4s image quality isnt much better then the older model d3s or even a d800 at half its price.