Will JFBConnect Joomla 3 work with Rsmembership?

JFBConnect creates 100% standard Joomla users that should work with any extension. The only subscription extension I know that has specific integration with JFBConnect is PayPlans. I'm not sure of the level of integration or what features their integration provides, but it may help.

Beyond that though, as noted, any user that registers with JFBConnect should be able to choose a package and subscribe to whatever your site offers without problems.

I hope that helps, but if you need anything else, just let me know.

Thanks,
Alex