Canon EOS 5D Mk II Vs Mk III

I've had the MkIII for 4 months and it's worth every penny. The autofocus is much more accurate. ISO is improved, and I'm finding I'll shoot at higher iso's more often. I just shot a wedding reception at 6400, and I was pretty pleased with the results. At lower ISO (50 - 400 range) picture quality is about the same.