The 1927 and original versions are a lot better than the last revision. I adore the 4th concerto.
If you are actually expected to play with an orchestra, or a competition accompanist, it's probably not a good choice at all. Chances are you will have very little rehearsal time, and Rach 4 and Rach-Pag are really very difficult to coordinate. If you are working with your own accompanist, I'd say go ahead. I'm not really a big fan of this concerto, but I don't see how a competition performance would hurt at all.
im going to see the Whale play it in november should be good
So are you saying there are three different versions?
Totally amazing and beautiful work, although the orchestra is overdone. Great stuff.