My 5DIII just arrived, and so far I'm really impressed. The images are very sharp, take post well, and have excellent color. If you can get in on one of the Ebay deals, its totally worth every penny of the cost difference over a 6D. I totally believe those folks that never regretted paying full price...its an awesome machine.
Just a note on the AF system - it is only the newer lenses that work with the closed loop feedback capability of the AF system. All lenses, regardless of age, will still benefit from the sensitivity and number of AF points available. So you do not NEED brand new lenses to take wide aperture photos. Just as you can get sharp photos at 1.2 on a 5DII, you can get them with the same lens on a 5DIII. If the lens had the new position feedback sensor it would just be EVEN MORE reliable.
All that said, I was going to get the 6D if the Ebay thing hadn't happened. It looks like a great all around camera for non-sport shooters, and you have that piece covered with yoru 7D.