've been trying to add up how many people on this site are jumping to Nikon "if the 5DMIII/X..."
I doubt many people that say they're switching to Nikon will actually do it. Expanding upon that, I'd say less than 50 percent of the people on here that are contributing to the 5DIII hoopla will actually buy one for various reasons. Maybe the product won't be what they're expecting. Maybe it will exceed their expectations, but when push comes to shove, they'll find a better way to spend $3,000. That's why it's called "hype," after all
I've got a D800 on pre-order, but if Canon counters with a competitive 5DIII, I'll cancel it and stick with Canon. However, if I didn't make a living with my images, and photography was just something I did for fun, it wouldn't be worth the hassle of switching systems.