I enjoyed reading your 5DMIII review. I really like the 5D’s auto focus, image quality and ability to capture images at high ISO’s. With its superior AF system, I am realizing a higher percentage of keepers.
The HDR capabilities of the 5D are terrific, although I prefer to develop an HDR image myself. It is fun to see an HDR image created on the spot. I have not tried multiple exposures, but I think this could be beneficial to certain action shots.
Low light capability is also superior! I have used the 5DMIII for NYC skylines as well as capturing Bruce Munro Light Installations at Longwood Gardens. I have examples of these images on my website at http://www.marcschoenholz.com/Places/Light/Illuminating-Light/24452420_JsfPMR#!i=1995203174&k=GhnLwSh
I am also capturing bird images with my 7D. The 1.6 crop factor of the 7D makes a big difference versus full frame. Overall I think the 5DMIII has a “better” focusing system then the 7D. IMHO both the 5DMIII and 7D are light years ahead of the previous Canon cameras (excluding 1-series). I wonder what the next 7D will have to offer.