DS (7 at the time) and I were unable to find a spot in the HRH pool where actual *swimming* was possible. It was all far too shallow, seemingly to allow people to sit for hours with their drinks, listening to the live band.
There is a small area that gets deep, but that's for the slide (which DS loved madly), and you have to swim out of that area so you're not smashed by the next slider.
HRH pool is great for people-watching, live music-listening, drinking, and sliding, but from our experience, not for swimming.
Portofino has the slide, and there's some room for swimming, and it has a sandy bottom on the shallow side. DS loves the whole area. There are two hot tubs in that area (I only mention hot tubs for this hotel b/c we didn't use them for the other hotels and I don't know about them).
RPR is best for actually swimming from point A to point B. It has NO slide. It has a water play area that's themed like a cruise ship. When we went they also had a volleyball-type net strung over part of the pool, and people were having a great time with some sort of ball.
Of course,there are also the quiet pools! We only experienced Portofino's other pool, and it was LOVELY. Great for swimming. No slide at all. They do have a hot tub and what seemed to be a cold plunge pool right near it, but maybe it was just a hot tub with the heat turned off, LOL.
For everything else, HRH is definitely the *coolest* to be in. RPR's lobby is absolutely lovely, but we found the grounds of Portofino to be beautiful and peaceful as well. IN the evenings they have opera, and there have been (when we've gone) lots of people in the piazza waiting for food, having wine, etc.