The RIC is the restored International Cut. It is bascially Superman:the Movie, with every deleted scene in it. There are several versions of this available, one that was taken from a laserdisc or DVD, I don't know which, with the additional scenes added in. Another is a rip from a VHS recorded from an airing in Australia. There was supposed to be another copy that was aired in the US once, but I've never seen it.
I agree with Zombie84. Some of the added scenes are too much, and cause the movie to drag in places. The DVD(SE) adds in scenes, but not too many to where is becomes overwhelming, IMHO.