Mostly what Simon says!
RTR map is also expanded east to beyond Bartix/whatever

EB take scripting to new different level compare to anything!! Amazing stuff.

Think also models and animations more different from vanilla in EB.

But now EB is beta, very buggy.
RTR is in best shape ever with 6 "Gold".

Currently RTR for play, EB to help find problems and so help most ambitious project to success, or to glimpse some exciting new thing.