I live in Belgium and am an amateur photographer, but have been shooting Canon cameras for many many years now. My current camera is still an EOS 40D, yes. Didn't want to upgrade to a pro model until I knew a bit more about the beautiful art of photography. Didn't want to upgrade to 50D, 60D or even 7D, because the difference in final image quality was too small for me. Been seriously upgrading on lenses though the past few years. 2012 promised to be the year of taking things to a higher level. I had very high hopes for the 5D Mk 3.
After reading a lot and looking at many pictures I think Canon is making exactly the same mistake as Nikon did a few years ago with the introduction of their D700. I think that was a far better and far more sophisticated tool than the 5D 2 in allmost every respect. Except for resolution (and video). The 5D 2 had allmost twice the resolution of the D700 and that was what people wanted at that moment. Being the lesser camera than the D700 they still sold truckloads more than Nikon with their D700.
Now we see the same thing happening with the D800 and the 5D 3. I am absolutely convinced that the 5D 3 for the majority of people will be a far better and more versatile camera than the D800. Except for resolution (and maybe sharpness). But, just like a few years ago, that is exactly what people want at this moment. My guess is that Nikon will be selling truckloads and truckloads more of the D800 than Canon of the 5D 3. Let's not forget that the whole media landscape currently is about high, higher and highest resolution.
Nikon and Sony, 2 of the biggest multinationals in photography equipment, have picked the card of high resolution. That alone should say enough. If you want to sell a lot of your product, than give the people what the people wants. As the Romans already knew. That's the most basic rule in marketing. Canon doesn't seem to be willing to accept that as a fact. If and when the market dictates the need for high resolution cameras, than it's very foolish and dangerous to neglect that. The 5D 3 may be as good as it gets, but taking a look at photos from the D800 makes my stomach turn with envy. Never seen anything like this from a DSLR. The amount of detail is simply from another planet and makes the 5D 3 look rather pale.
I am convinced of the fact that a good photographer needs to study the composition of his photo before taking it. But I can assure you that many of these so called very good photographers will be cropping on the D800 photos like never before, applying the rule of thirds, etc. in post processing and presenting stunning photographs. Of course they will never admit this, but nonetheless Nikon gives them the perfect tool to do this, without being noticed by the majority of people.
I, for myself, will not be turning to Nikon, because I have too much invested in Canon glass and I'm not making any money out of my photography. So I won't buy the D800. Guess I will be sticking with my 40D for another while. I have the money, but I won't buy the 5D 3 either, because next to each other the photos of the 5D 3 aren't worth looking at when compared to those of the D800. We're not even talking about the price difference here. I am a faithfull Canon customer, but very disapointed in Canon's marketing strategy. Sticking to 22 Mp will cost them a lot of money. But that's only my opinion.