Overly simplified , but.....
Rookie + High Speed Rotary = Bad news, sometimes really bad news.
Rookie + Random Orbital = Decent results with little chance of real damage to paint.
The Rotary is capable of much, much more than the RO. Much, much more good things and much, much more bad things. Great tool for those with the experience/talent to use it.
The RO can be used right away by just about anyone.
Porter Cable, DeWalt, and Makita all make rotaries.
Porter Cable and DeWalt also make random orbitals. Makita may also make a RO, but I've not seen it.
Charles