UPDATE: I purchased the Canon 7D mk ii. I went yesterday to try it out and really wanted to see how the ISO was. When I shot in fairly good lighting (cloudy and dim lighting, but still good) I was blown away at how well it did. I amped it to 3200, could not see noise. then to 6400 (you would think to see something at least).... nope. even when I zoomed in on the picture I could see it some, but lightroom would clear it real fast without losing deatil.
in low light the ISO still performs really really good. at 3200 it looks really clean and no noise. at 6400 you can see it very very very mildly. when zoomed in to 1:1 you can see it mildly but it can be clean easy. but here is the crazy thing............. I amped it up to 16000 (yes sixteen thousand) and there is noise of course but it is not that bad. something that can be cleaned up and lose a little bit of detail.
now here is my down side to all canon gear (and this could be user error). but there is a lot of times when my images are not that beautiful tack sharp. like when you zoom in and can see the detail in someones chin hair for a 13 year old kid. and that is on all the lenses. the 70-200 is still a 95% awesome, but it just rarely gives me that OMG 100% awesome. and it does this on the 7D mk ii. so do you think that it is me? should I try to mess with adjucting the lens in manual settings?