Ah Pek: Never ceases to amaze me how people can make statements like "the pics aren't any better than 5D2!". They still think what makes an image special is the camera. These people think they can perceive a difference without a 100% side by side comparison! LOL!
What about people who already know how to make good images. Can they talk about the pics if they are better than 5D2 or not?
Entropius: Something that I've wondered about about the D4:
In the press release, Nikon makes a big deal out of the fact that some of the autofocus points will focus with lenses dimmer than f/5.6; they say that some of them will work down to f/8. Canons, I know, also have issues with this.
However, every Olympus DSLR will quite happily autofocus at f/7 (even my old banged up E-510, with its 3-point AF sensor, 1 point cross sensitive). It'll even AF at f/11, using a f/5.6 lens with a 2x converter -- although it's slow in poor light.
Does Olympus have some sort of magic AF sensor? In my experience Olympus single-shot AF beats Canon's hands down (although continuous AF is a whole different story).
It is about precision and how fast it can focus.