except, oddly enough, when polls are held by the Nikonians on whether people are happy with the D800, 90% of them say no.
If there's truth to those figures, it's really not surprising. While the 5DIII represents a logical evolution of the 5DIII, the D800 is a complete departure in philosophy from the D700. The 5DIII is essentially a 5DII that's just better all around: nicer AF, faster FPS, superior build quality, dual slots, etc. I can understand why current 5DII owners might not think the added feature set is worth upgrading to the 5DIII, but if you like the 5DII, chances are you'd enjoy shooting with the 5DIII.
As for the D800, it's a high-res, slow speed body that's replacing a low-res, high-speed body. I'm sure many D700 users were hoping the D800 would be a baby D4, but instead they got a body with triple the resolution and half the burst rate. It doesn't change the fact that Nikon has built a very impressive machine, but the way I see things, Nikon shooters have more of a reason to be disappointed with the D800 than Canon shooters do with the 5DIII. The obvious appeal of the D700 was its balance of just enough resolution and a lot of speed, and now it's been replaced with a body that has a sh!t ton of resolution, and a big reduction in speed.