The HRH does have the slide, and it's closer to the parks with the walk being about 5 minutes. The RPR is slightly farther away, being about 7 minutes. Their pool has the ship wreck with water guns. If dragging kids, you'll probably have to add 5 minutes to these times.
I'd say it doesn't matter. If you already have a ressie booked at the HRH, and you like it, then stay there. If you really want to know what the RPR is like, then you can change it, or you could just walk over and check it out on your visit. You are allowed to use any of the 3 hotel pools. So if you want, you could get the kids together, and say you're going on an adventure over to the RPR to check out their pool. Same for the PBH. Just tell the kids if they go along with your request, you'll buy them a slushie drink from the bar. Otherwise, they'll say no as a way to control you.