Odds? I don't even buy tickets!
I am not a big fan of FF at all. Don't need it. Not into WA. Canon seems to be lagging behind on the development of the 7D II, (iDs are too BIG!) maybe because everyone is jumping on the FF bandwagon. ("FF" and mega-MP sells cameras!) For what we do, you end up throwing away a lot of pixels. FF cameras with a crop mode make good sense though. The wider field of view makes it much easier to find and track things.
I don't buy the "net" numbers. A 700mm lens is a 700mm lens, no mater what you put it on. It is all about pixel pitch; small for detail, big for punch.
I like the 600 too, but unless you get the Mk II version, to the tune of what, $14,000?, it is just too heavy! The new Canon Mk III TCs have made the slightly shorter lenses much more useful. Big improvement in TC technology!
WYSIWYG is good in theory, but it has drawbacks. Fine for static subjects, problematic for moving subjects or when moving the camera. If I have my camera setup for it, it makes the EVF even more restless. On top of the normal flickering caused by movement, you get the constant flashing of the EVF brightening and dimming as you move. That becomes especially bothersome if there are large differences in the brightness of different areas of the subject. So your eye is also going crazy compensating while concentrating on the actual subject. I prefer to turn the boost on and let it react more slowly. I don't need to see everything in the VF exactly the way it is going to be in the end. That is what PP is for. Get the focus and exposure right and think about everything else later. Like Yogi Berra once said when his batting coach told him to use his head, "I can't think and bat at the same time!" Same with photography, esp with a scope. I have enough to worry about just getting the focus and exposure right, not to mention finding and following the bird.
About OVFs. I find out of focus object much easier to see in an OVF than in the EVF. I find it therefore easier to single out a bird on a branch, for instance, with an OVF. The smoother blur of the out of focus bird is just easier to identify. But I love the size and brightness of the EVF, no question!
