Here is a piece I just read and found it interesting...
D800 vs D4s For Wildlife in Low Light & Long Lenses
D800 vs D4s For Wildlife in Low Light & Long Lenses
Great find pedroj, and that backs up my thoughts exactly.
I have D800e and a D4s, but find myself almost always using the D4s nowadays. It's just so accomplished in the autofocus department in comparison to the D800e. I can even put the TC2.0e III on my 200-400 f4 and the D4s will bang in a super sharp image at f8. The D800e obviously needs a better photog than me to get super sharp images, at a local air show recently, I had the 200-400 on the D4s and 70-200 f2.8 vrII on the D800e, both fantastic cameras in their own right along with the lenses.
However, the D4s images were outstanding, almost every one. Whilst the D800e gave me great images also, just less of them that were super sharp.
Where the D800e is better is in landscape and architecture, there the extra resolving power of the 36mp really stands out against the D4s. Perhaps that's due to the objects being static and you can take your time over focussing.
Got to come to the conclusion that the D4s is more forgiving in the focussing department along with fact the the Expeed 4 chip is just so much better than the D800e Expeed 3 item.
A perfect example of how absolute megapixels does not always translate into better IQ. I am giving serious consideration of getting rid of my D700 and going with a used D3X