Havent camped there, but have visited several times (we're local). The falls are worth the trip. There's a couple of nice campgrounds on the other side of the interstate you may want to investigate before booking a reservation.
BE SURE to schedule your trip when a Moonbow is due. That alone may make your decision to stay in the park so that you don't have to drive from another CG to see it at night. Last time I talked to a ranger there, they leave the gates open on Moonbow nights so that isn't a problem.
Nice little park imo. Good informative website last I looked too.