We went from RPR to PBH for our second trip for the same reason. And while it isn't like you're going to be amazed at all the extra room, it is basically noticeable. If I recall correctly, there's a vanity outside the "toilet/shower room" at RPR, whereas it's all inside the bathroom at PBH. Which is probably how they were able to find the extra space for "living" at PBH, along with adding a few square feet.
RPR is like a tropical resort; PBH is like a villa in Italy. They are both themed, just different themes.
We're going back to PBH in February, payin' the big bucks, because we really loved it. (well, and b/c all the normal rooms at RPR were booked, leaving only the expensive rooms that cost $100+ per night more than PBR, leaving us without the *option* to even *think* about it, LOL)
Now...it's been recommended to check out things like the King Suite at RPR, if space is the issue and you like the resort more.
The fabulous things about the Universal onsite resorts is that you can visit, you can swim, etc at any of them, leaving only the room and the theme as parts of your decision-making process. Love that!