JFBConnect uses the built-in Joomla methods for creating a user. We create a new instance of JUser and then call save() on that user after we've setup the proper data. That save call is controlled completely by Joomla and that function does trigger the onUserAfterSave function in the user plugins. Our Sendy newsletter plugin and many other User plugins we know of properly receive the onUserAfterSave call and can 'do' something with the new user.
Similarly, we use the standard JFactory::getApplication()->login(...) function to authenticate new users. That is the standard Joomla call for logging a user in and it (core Joomla) automatically triggers the onUserLogin event. Again, JFBConnect and many other plugins properly see and detect that call.
I'm not sure what's going wrong with InviteX. I've honestly never used it, though I've heard many good reviews of it. We also know that many users have both InviteX and JFBConnect working, though I can't say they're using it for the same functionality you're trying to accomplish.
I hope that helps explain things. From our end, we're doing everything right. If we weren't, there would be a ton more support requests to support extension x, y and z. It benefits us greatly to do things the 'Joomla way' as it makes sure we're doing it right.
Thanks,
Alex
Integrating JFBConnect with Invitex
