I have been using NiceMemberships for nearly 2 years to collect recurring subscriptions from PayPal to access my site. The product allows you to offer different subscriptions to different parts of the site.
It is very easy to use, you just enter a short coded string into a normal Joomla document. You can determine which access levels can see which strings etc.
All transaction (incoming payments) held in the database as are the subscribers. The subscription period can be for a specific length or on-going.
It is very easy to install and set up.
Richard Charlesworth - Virsel Limited