Someone at work noticed that if you read a list of cg films in chronological order it appeared to read like a best to worst list. So we graphed up the http://www.rottentomatoes.com/ film scores Vs year made. Here's what it looks like. (Jimmy Neutron is mistakenly missing)
Also worth noting is the production house stats. Sure shows why Disney bought Pixar.
Production House RT Average Ratings
Pixar 5 films = 97.2%
Dreamworks 5 films = 72.6%
Blue Sky 3 films = 66%
Disney 3 films = 28%