I think what gets lost a bit in the discussion of high ISOs is that in addition to more noise, the color quality can take a substantial hit. Before I replaced my 7D with a 5D3, I would only go to 3200 in emergencies, as much because of the damage it did to color rendition as for the luminance noise. With the 5D3, I get acceptable noise and color at 3200, as good as the 7D set to 800. I've switched to the 5D3 for my bird photography because I can get away with higher ISOs. Despite the lower pixel density, I'm able to get shots that look as sharp or even sharper than equivalent 7D shots because I can use less noise reduction. If Canon comes up with a 7D Mk II that is a stop better noise-wise than the original 7D and has ~24 Mp I would probably go back to crop land, at least for telephoto work.