My dad purchased a 2014 CAAD 10 105 new, I test rode it and took have around 200 miles or so on it. It's an amazing bike, fast, light and comfortable, much more comfortable than my 2013 SuperSix (non evo). The only parts I did't like were the Tekro brakes and the Schwalbe tires. It's super capable and worth upgrading.
I'm 5' 7" and all of the Cannonades I have owned have been 52cm and fit me perfectly but definitely go for a test ride before you buy.
From what I have seen lately, $800 seems to be on the lower end of the market for a CAAD 10