I think no matter how good the 5D3 really is, the Nikon D800E should be easily better. Cannot talk about percentage but the complete lack of AA filter in combo with 36MP of the new sensor with also higher DR - what should be wrong here?
What I do not really get - I also owned (own) both systems and while I always liked Canon L glass, I must say that Nikon is topping it if you consider their Nanocoated glass - so why do you say C glass is better? I surely value your opinion but I am just interested.
If comparing lenses, I'm only interested in how the images are drawn if I am shooting wide open from what is sharp to the out of focus region and bokeh, and closing down to get sharper images. This is my short answer and I know is very subjective.
While I hate to compare what isn't directly comparable for example what was 21MP vs 12MP. I also cared for what was also translated from the sensor of the images to Raw processing software, that being LR.
While seeing a lot of details matter to certain degree, what was coming out for say 35L vs 35G glass, I see no wow factor from the Nikon glass and the same goes with the 50s. Although with the 50L costing $1.5k vs $600 for the Nikon 50G. The same was seen when I compared the two 70-200, both the latest versions. While both were improvements of the old which make them neck and neck, I would rather use pick up the canon. It's hard to compare directly, but I was interested immediate satisfaction of the images and Canon gave me immediately response as to what I preferred as images that wow-ed me. Nikon is a solid performer, but like I have said previously I cannot feel that impressed, nor could I get the colors I needed. When shooting asians and my baby boy, that was immediately clear for me! I think this is very much a personal response, while I know some friend share the same feeling, I not out here to convince others of the same.
This isn't absolutely fair argument, since I returned the Canon 16-35L II and just stayed with primes. While on my Nikon I stuck with a more inferior lens and was happy, that being the 17-35mm, because I care about attaching ND filters at the time!
Again, i would agree with you about the D800E having the edge for detail, as you can see from what I typed above, this isn't the only thing I care about. I'm not saying this for you either, but what gives us the images we are after is what we will settle with in the long run. I haven't quite canceled my pre-order for the D800E yet, I'm realistic, but I know what gave me the results in the past. I also love my Nikon 24-70, which others have said they felt differently about it, and yet I cancelled my pre-order for the 24-70L II from Canon recently, because I want to stick with primes.
I know dynamic range is hot topic and how a lot of people care about this to varying degress and how to achieve this. I didn't think or see that the D700 gave me this advantage by a clear margin. So this was the main reason why I let my D700 go earlier on and kept chugging away with my 5D2.
I know my explanation is confusing as hell, but we are organic thinkers and beings, and art is always quite a subjective thing. Ultimately I felt Canon WOWed me more is what I come down to. So despite this minimal upgrade as it seems, I'm happy to continue the journey!