I use JomSocial and had tried its Facebook Connect feature, but was seriously disappointed at all the permissions that it requests of the user. There were like 10 requests or something, including one that asks the Facebook user to allow the app to access their private data at any time, even when they are not logged in. Facebook Connect is great, but a lot of users have privacy concerns and the fact that JomSocial's implementation doesn't let you adjust the permissions requests is a detriment to its usefulness.
JFBConnect can get the job done with only a single permission request, with additional requests being optional. And the JFBLogin module is much more flexible than JS's Connect implementation at allowing you to modify its appearance. Bottom-line: if you want Facebook Connect integration for your Joomla site that is flexible, won't scare away people with unnecessary permission requests and which comes with superb support from its developer (thanks, Alzander!), JFBConnect is your answer.