I can't imagine anybody being a full-on Pixar hater. I'm not a rabid fan of the company, but even their lowest tier films (Cars, lets say) equals out quality wise to the best efforts of any other CGI movies out there (Cloudy With a Chance of Meatballs for example).
Their movies are generally peerless when it comes to actual tech and visual innovation, even the aforementioned Cars just looks terrific all the way through. If there's any company wide flaw you can sling at them, its that their "outsider-redemptive" stories could be getting formulaic, but their plots and settings never are so that doesn't stick so well.
Really, I consider Pixar to be a positive force in the movie world, and I'm very glad that kids and families have good, quality material to enjoy together without a trace of the nominal crap that infects most other family movies. No cynicism here, Pixar is good.
Oh, and I'd put Ratatouille at the bottom half, but its not bad by any means.