PBH is a "resort" hotel, which means it is highly themed among other things. When they started out, they made much of how they were planning on being Orlando's first 5-star hotel. There's been little talk of that lately (they got 4-stars first go 'round), but that goal meant a lot of fancy detailing in the rooms -- marble in the bathrooms, for example. The rooms are bigger and posher than at HRH, the grounds more extensive, more dining options, more pools, etc.
PBH is also a big meetings hotel (lotsa ballrooms and meeting spaces), which means that from time to time it gets oversold, which has caused problems for some people who have come to these boards to complain.
HRH is a very cool upscale hotel, but aside from the rock memorabilia scattered modestly about, it is not as extensively themed as PBH. Rooms are smaller and not as posh (although if you want posh you can pay for it in the form of an elaborate suite).
HRH is literally minutes away from USF. I timed it once and it took me 6 minutes from the hotel to the inside of the park. It takes another 5 minutes or so to reach IOA.
PBH is farther away, about 15 - 20 minutes walk, which means that few people walk it. There is boat transport from both hotels but it hardly makes sense from HRH.
Hope this helps.