The pool at RPR: is big, spread out, and has a big waterplay area sort of attached to it. We've been there when they had a net across part of the pool and people were playing volleyball of sorts which seemed like fun. I think they have a hot tub, too. The environment is pretty, tropical, and lush-feeling (even though we were there for the infamously COLD December of 2010).
The pool at HRH: is not as big, is incredibly shallow. has music piped in under the water, but I couldn't find a spot in the pool deep enough to put my head under water to hear it. LOTS of people sitting in the water, drinking (please let them get up in order to use the restroom, please...). But the slide, according to my then 7 year old son, was pretty awesome. At the bottom of the slide is a nice deep area, but you can't use it for swimming b/c, of course, there are people plunging into it from the slide! The environment is pretty, especially with the mission-style building halfway surrounding it.
The main pool at PBH: has half of the bottom covered in sand; that's the zero-depth entry part. The other part of the pool is nicely deep. I believe there are two hot tubs, sort of out of the way, at least they felt out of the way. Comfy loungers. They have a slide that DS liked. It *felt* the most luxurious of the pools at the other resorts.
The quiet pool at PBH: (it might be *one* of the quiet pools, I haven't gotten it all clear yet, but it's the one we went to)....good for proper swimming. Nice big rectangle. Loungers all around. Hot tub and cold plunge pool (at least I think it was meant to be a cold plunge pool, LOL). Gorgeous. Felt like I was in that 80s ad showing a fancy person swimming while a plane went overhead (maybe for Ban du'Soleil?) if anyone else remembers that.
But as was already said, they allow pool-hopping; all it takes is a walk, a pedicab ride, or a boat ride (or combo) to get from one to the other! Just bring your keycards.