it sure is the better general use camera but: i am doing stock, portrait, landscape stuff and the occasional low light event. And most of those are parts where the d800 shines and honestly destroys the 5d3. and it´s nearly the same price as a 6D.
I see one part where the D800 is clearly better, if
you regularly produce large (i.e. >30") prints, and that's landscape.
I'm one of the people who complained when these cameras came out, and I still complain. The 5D3 should be priced lower, and there should already be a high MP body from Canon. That said, you have to keep this in perspective. For 95% of photographer / subject / print size combinations, the D800's sensor advantages simply do not show up. If you are a careful (i.e. tripod mounted, pro glass, perfect technique) landscape photographer who prints really big, then the D800 advantage is significant. If not, then it's a non issue.
and they even have the d600, which is cheaper and better then 5d2 and 6d and on the level with the 5d3 (besides the build quality). But obviously this one is out until they fix the sensor dust thing.
It's not as good as a 5D3. But it does clobber the 5D2 and (likely...it's not out yet) the 6D.
Yeah they are the market leader but look at their products: A 5d3 which is no real IQ improvment over the 5d2 - ok af, a bit high iso and video.
OK AF??? No, sorry, excellent AF, which is one of the things that distinguish it from the D600. The high ISO is also quite good and the JPEG engine when shooting high ISO is phenomenal.
6D - a camera nobody knows who it is for... not rugged enough for landscape, no pc sync for studio, too much MP for awesome high iso.
MP is not related to high ISO in the manner you believe. We don't know much about the 6D yet. It's supposed to be an entry level FF, but I think Canon needs to slash the price for it to fulfill that roll.