Probably just depends on preference. I much prefer Royal Pacific, even with the smaller rooms. It's closer to walk, and we like the resort. The pool was fun when the kids were young.
Portofino is nice too though, also has very nice pools, and rooms are larger, but we didn't like the bathroom layout the first time, and the last stay was not great at all. We often had to wait for a second (sometimes a third) boat, or walk. They were doing a LOT of construction, and I know that influenced my opinion, but unless the price is significantly less, Portofino is my last choice of the 3 premiers.