I'd not get any, time hasn't been good to them. R/B/Y only has some nostalgia factor overshadowed by the numerous issues that plague them.
They don't really have that much to redeem themselves, the gameplay is extremely shallow compared to even G/S/C. The graphics even for its time are nothing to write home about and the story is almost nonexistent.
What it had going for it back then was its innovative idea that is hardly new anymore, and the ever-present social aspect in trading and battling.