I used RateMyProfessor.com until I realized that lazy students who were upset that skipping classes resulted in less than stellar grades were the majority of the reviewers. I switched to Pickaprofessor.com which factored objective statistics such as grade distribution into the overall review score. Sadly, pickaprofessor seems to have been bought or morphed into something else since I graduated.
Oh. I hate Mike Adams and I wish I had a T-Shirt to prove it.