I shoot with a 5D classic and a 7D. Between the two of them, they meet all my needs. After two years of work and sending them in to Canon service for calibration, they are working properly. And just as important, I understand the limitations of each one. I just have to pick the right one for the job and use it within its limits. (The poor autofocus on the 5D being the most annoying.)
While waiting for the 5D 3 to appear, I was pretty excited thinking that I could buy a camera with full frame image quality and the fast handling of the 7D. I even figured out how to pay for it at what I expected to be 3K in US dollars.
The extra $500 may not seem like much, but it was enough of a psychological surprise that it caused me to re-evaluate my need for a new camera and I decided not to purchase one. It made me feel like Canon was trying to take advantage of my presumed loyalty to the brand.
I will wait until the end of this year to see if the price drops into my comfort zone. Maybe when the supply chain is filled and all the early adopters have their Mark 3s, Canon will allow some discounting.
If the price does not come down (and assuming Canon does not come out with a new camera that meets my needs) I will have to think seriously about the full frame Nikons. Or maybe I'll just keep shooting with my current cameras until they fall apart!