Here's an annotated list of other sites that analyze fact checker report cards.
This site is awesome. Author Karen S. has the full data set of PolitiFact rulings and has done a lot of in-depth analysis on fact checking and fact checkers that you won't find on Malark-O-Meter.
Steve's also done a tone of work breaking down PolitiFact's rulings by topic, party, and even the occupation of the individual or group whose statement is rated.
This site is hilarious and aesthetically pleasing. I seriously wish I could code CSS and PHP as well as J. Kalgreen can.
The PolitiFact toyed around with a Truth Index, which averaged Truth-O-Meter rulings on a scale similar to Politi-Psychotics' and Quibbling Potatoes'. They don't compare across individuals or groups.