My 100-400mm f/4.5-5.6L IS II works great on my 7D and 7D2 cameras but, I am disappointed by its performance on my 5D2 (which works just fine with my 70-200mm f/4L IS lens).
It seems to vignette at image left and right and doesn't seem very sharp, although I shot this ripod mounted.
Here is the full frame of the image with the example of the vignetting...