Canonrumors.com and the 5D
Canon actually released a statement about the light exposure issue with the 5D MKiii.
As others have pointed out, canonrumors.com is a rumors sight. The problem is that a lot of the people there seem to forget it, most likely because many Canon shooters have been waiting for a 5Dmkii replacement for a long time. The replacement cycle this time around was longer than it was during previous updates to Canon's FF bodies.
Also, take note that the members of Canonrumors.come seem to invest more emotion in their equipment than they do the actual photos they take. It amazes me to see people bicker ad nauseum about personal opinions and technical details that have little to do with producing an affective picture. As such, the conversation in the rumors and gear talk sections tends to be somewhat hyperbolic and rather fatiguing. I read canonrumors.com far more sparsely than I used to, and only now to look at the work of some of the best photographers the web has to offer. I think that site is far more valuable for its artistic controbutions to the web than for its rumors discussion forum.
Take what you read there with a grain. Otherwise, you will end up discounting some rather excellent Canon equipment.