Rabbits Reviews seems to be the most popular as they hold some great search engine rankings. They have a nice desing, some good reviews, and a real catchy theme.
The Best Porn is a really cool site as well. They have a ton of information on paysites and a lot of work has gone into it. I'm really impressed by how thorough they are.
After that, there are a lot of other good ones. Porn Inspector, X3Guide, Sir Rodney, and more. I've been working on my own (
http://www.pornkangaroo.com), and hope to even be mentioned in the same sentance as some of them someday.