JFBConnect is robust and stable, and adds far more Facebook integration features than just the login and friend invitation that I was looking for. The extension has a very professional design and is thoroughly documented, which is something I've found lacking in the majority of other Joomla extensions.
The developer is very responsive and often goes way beyond standard support scope, even to the point of offering code hacks to implement non-standard features and tweaks.
I'm more pleased with JFBConnect than with any other Joomla extension I've purchased. The subscription price was money well spent.