I am currently researching membership sites. Ray and I are planning to start one and have gotten several suggestions. I saw this insightful post providing a good explanation of several sites. When you combine the information in this post with the meaty comments you get a fair and objective overview.
So, if you have questions, submit the question as a comment. The author, Charly Leetham knows what she is talking about and provides training and information just right for folks who want to get good information but not at a frantic pace.
I have decided to add her to the list of great online trainers I have met. So read this insightful post discussing a few of the popular membership sites.