I have been developing sites using Mambo first and then Joomla for many years, but this is the first time I've been asked to create a paid member's section, and this component was exactly what was needed.
Warning to US users - I am pretty darn sure the manual was translated from another language, which makes it a little tougher to get through, and it is not quite as in-depth as I'd like. I had to install and set up the entire thing before I was sure it actually did what I wanted, which was to integrate with the Joomla User module. It does!
Despite some aggravation with the less then detailed "detailed" instruction manual, the tech support is OUTSTANDING! Great tech support combined with a fantastic component are why I rate RSMembership five stars.