Shot with my 5DIII for the first time in the "real world" yesterday (a friend's civil wedding, shots in a park, and dinner).
I'm happy with the results. I was mostly using a 24-105L and later my Tamron 24-70 2.8 VC. I also used my Sigma 70-200 2.8 OS, and Canon 50 1.4 for a few photos. It worked well with all those lenses. I selected cross-type points only in the AF menu.
I also had my 6D with me with a 85 1.8 on it.
I probably had too much gear for the occasion but the photos came out well
I was using only SD cards... When I sold my 7D, I also sold all my CF cards, now I regret that. They are so expensive. There is a good deal on the 32GB Transcend cards (around $30) but there are quite a few reviews about corrupted cards. I did own one of these (16GB) and never gave me a problem, but I'm not sure if I should buy them again. There are some decent Sandisk and Lexar 32GB cards starting at around $65-75 on Amazon, but I'm not sure what I should buy. I am very heavily invested in SD cards (I have over 300GB in fast cards), so for now I'm just using SDs until I need dual cards and/or speed.