I think you are correct that I would be a perfect candidate for FF. I have almost no interest in wildlife unless it is kind enough to land on my patio for easy shooting. Not too serious in the sports either. What I do shoot is my kids, and often indoors with less than perfect light, and I don't like to mess with flash when I can avoid it.
I also like the idea of keeping the T3i and even using 2 bodies at the same time. I would, however, probably sell the 17-55 if I got a FF with a 24-105 or 24-70.
I very, very nearly bought a 5D3 during the Monday sales a couple weeks ago. The one thing that stopped me was a.) wondering if the 6D could do the job just fine, and b.) worrying what the heck is the deal with 5D3 focusing in low light?
Has a consensus been reached on that 5D3 AF assist lag question? Some say it is the somewhat weak AF beam on 580 and 600 speedlites, but others say it is bad with the 430's too. Some say a Chinese speedlite may (will?) fix the problem. Some suggest you ignore focus confirmation and just mash the shutter button all the way. No one seems to be sure a firmware fix could do anything or not. Still others say they don't even notice a problem, or that maybe there is only a "bad batch" of bodies out there.
Has anyone specifically tested the 6D for af-assisted focuing speed? Can anyone say for sure it is faster with AF assist than the 5D3 or not?