Thank goodness they are very skilled photographers and know what they're doing because their cameras are not giving them the slightest advantage vs. Canon. Canon "banding getting worse" ... what banding? Canon "falling behind in color sensitivity"? ... I wish Nikon color were as good.
You seriously did notice the banding got worse going for 1Ds3 to 5D2? Or 40D to 50D? And then better again from 5D2 to 6D (although maybe still a trace behind the old 1Ds3)?
You actually think that many Nikons have not had a lot less banding than stuff like 50D,5D2,5D3,1D4,etc.?
Maybe you don't ever shoot to where it matters, but that is something else.
You wish Nikon color sensitivity were as good? It's better.
As for what color is better overall, not just talking color sensitivity, that is a very complex topic with no easy answers. Overall it seems Nikon has filters that allow for more accurate color overall on average although Canon make make certain skin types easier to pull off nicely. It's a very twisted subejct and it varies model to model and in many cases there is probably no universal answer comparing any given body to any given other it might depend upon the very exactingly specific question you ask. But in terms of color sensitivity and metamerism overall on average Nikon has often been a full stop ahead recently.
1Ds3 to 5D2 -- that's going from the a top of the line model to a model costing half as much. You're really stretching here.
40D was same generation as the 1Ds3 and also had a lot less banding than the more costly 5D2 which was of the really bad banding generation along with the 50D
40D to 50D -- that was 2008; we are now two models post 50D. You're really stretching to prove this alleged decline.
How it is stretching anything. you said there was never any decline, there was. They spent a few generations getting worse before now climbing finally back to where they had been over half a decade ago.
5D2 to 6D -- the 6D is significantly better in image quality. There is no banding, let alone "worse" banding.
That is what I said, with the 6D they finally got the cameras back almost to where they had been in the 1Ds3 era.
I used two 5D2's for a total of nearly 400K exposures. No banding problem. I must be shooting "where it never matters", or perhaps I don't massively underexpose.
How many times does it need to be said that it's not about underexposure!
I didn't say Nikon has less banding. I said banding is not an issue with current Canon models. And there you go again with the 50D.
You said you never saw any changes and that they had never risen and declined and risen again, something a heck of a lot different than there is no banding with current models. And the latter isn't even quite true since while the 6D and 1DX do pretty well with it they are still a touch worse than old 1Ds3 in that regard and somewhat worse than most of the Exmor cameras at any price. And the 5D3 is very much a current model as is the 7D and they have a goodly amount of banding at low ISO (although the latest processing software is fairly good at hiding it with the 5D3, but when you are really pushing DR it still shows with the 5D3, in fact if it didn't, then how can people say the 6D clearly does better?).
As for Nikon color being "better" ... I've seen too many examples to the contrary.
Overall as a whole there sensors have been more color accurate overall at the RAW level. As I said it's a very complex thing and it also depends a ton upon what software and profile you use, tremendously so and also what you care about, if you care about a certain skin type under certain lighting type by far the most than Canon colors may overall seem better to you, if you care about some other aspect than very well maybe not since Nikon has tended to distinguish more fine shades overall and store them as RAW a bit more accurately as a whole, although no for every portion of the visible spectrum. There is no simple answer at all when it comes to color and there are so many different aspects to it.