I have to say, looking at the short that Nikon released for the D800, the video looks very clean and there's a bit more resolution squeezed out of the D800. What surprised me even more is that Nikon used the D800 for the low light short of Joy Ride and the D4 in the "Why Athletes" video. I would think they'd switch it around but I guess the camera speaks for itself:
The low light ISO is impressive, especially during the street scene with the hookers and homeless people. I'd say it's cleaner than the 5D2, resolution it looks like 7-750lpi vs the 600+lpi on the 5D2. Dynamic range looks very wide too.
Looking at the BTS MO, it looks like it was all shot in-camera vs using a recorder via HDMI.
In the MO itself, there's still some rolling shutter wobble and in a few scenes, the AF was searching wildly (even with brightly lit objects!). They were pulling focus manually as well. Overall, it's a great short demonstrating the abilities of the D800. I doubt it'll have the same effect as Reverie did for the 5D2. But the video portion of the D800 is very impressive indeed, and looks to replace the 5D2 as the FF35 champion DSLR for video. And that can only be good news for consumers as this will push Canon to react. The D700 preceded the 5D2 by 6 months. Let's see what Canon will produce with the 5D3.