..Making a brand choice comes down to more than hardware offerings, hardware quality, etc.
While that's true I don't make a purchasing choice based primarily on how something is likely to fail and be repaired.
I need results more than some sense of long term security so I can afford to choose accordingly.
Hmm, interesting that you would say you need results. What happens when your camera DOES stop functioning, and results are impossible?
It may not be the most important thing to you specifically, but I think in general, not just when it comes to cameras but when it comes to most things, people prefer a company that will not only stand by their product, but step up and fix issues, without introducing a lot of hassle, when something does happen. Canon won the professionals heart in the 80's with their AF. For a long time, they were the best AF game in town. Today, Nikon has definitely caught up, and at times surpassed Canon's AF performance. They do offer better IQ in a few models as well. But professionals still overwhelmingly shoot Canon. I can't imagine that the quality, responsiveness, and low hassle of their support doesn't play any role at all.
I'm still interested in what sort of real-world limitations the D800 may have that some people have hinted at but not substantiated. I haven't found any in my use of them. There was only a learning curve of getting used to how they do some things differently.
I wouldn't haul a D800 out for anything action related. It is probably capable, barely. At 4fps, it just wouldn't be fast enough to really zero in on the perfect moment in an action sequence. Hell, I consider the 6fps of the 5D III to be borderline good enough for my BIF work. There is also the situations in which you need a deep buffer for continuous shooting. Canon excels here...when you hit the buffer limit, you can still keep clicking away, albeit at a lower rate, as the buffer clears. The D800? It comes to a crushing halt, forcing you to pause while the buffer is cleared. That again puts it at a pretty severe disadvantage when it comes to shooting any kind of continuous action. The megapixel count, while a boon for some types of photography, results in huge file sizes...which can also be a limitation if you need to work through a lot of images in post (although that is not something relegated to just the D800...a high MP camera from Canon will have the same issue.)
If I had to pick a general purpose camera, and had to choose between the 5D III and D800, I'd pick the 5D III. If I had to pick a camera for landscapes, at the moment, the D800 wins hands down in a heartbeat. I could also use the D800 for macro work, if only I could slap on the MP-E 65mm 1-5x Zoom Macro