I love love love CBR. Very fun, and I think the theming is more fun than POR. CSR hasn't interested me too much.
That said, I gotta agree with Stacy. For theming, my first choice with a 4 year old would be AKL, bunk bed, savannah view (we had giraffes sleeping under our window at night). If $ is an issue, I'd actually opt for All-Stars Movie over a moderate. The themes are just more kid friendly. If theming isn't an issue, go for CR, the convenience is just unbelievable.
My dd has been way too many times from 3 - 7. Her favorites are AKL and ASMo and ASMu. (and HIFS.)