After spending about an hour going through all these links I am slightly concerned. I just bought one of these paired with the 5d mk ii and i've noticed that I've missed some shots that I thought were easy, and too many of the pictures have come out a little soft. It seems that our gallery does have a lot more "soft" pictures than the 70-200 f4 IS. I'm not sure whether our f4 would be better than their f4, but either way they seem to have more "tack sharp" pictures.
I'm not considering getting rid of mine or anything but do any of the others feel the same way?
F4 to 2.8 is it that big of difference with adequate light? Unless one has used a 70-200 a lot you are going to induce camera shake until one gets steady with a telephoto. That was my problem, rushing shots and not holding both hands steady enough. I seldom get soft shots anymore.






