We love them all, for different reasons, but Portofino is the one I'm least likely to choose when the others are comparable. For the most part, I pick based on whichever one is the cheapest. I love Hard Rock, but our last 2 stays at Royal Pacific reminded us why we love it too. I have it booked for a night in Oct.
I do very much like the size of the rooms at Portofino, they are bigger than the other 2, more room space, although quite a bit is allocated to this ridiculously large bathroom.
Negative for us is that the walk is at least double the others. Doable, but tiring and hot sometimes. First trip, boats were great, very quick, little wait, etc. Last trip in March, either waited for 2 boats , as they were constantly full, or we walked....Also, I was bothered quite a bit by the construction. But that should be over soon.
Portofino has a great main pool, and very nice 'quiet' one.
But Hard Rock and RP are good too, and you can pool hop if willing. we've never done it, but it's an option at Universal.
We rarely eat at any of the resort restaurants, so no opinions on the ones at the premiers. If you are at RP, it's easy to get to Sapphire Falls, or Aventura for good quick service.
Happy planning. They are all good!!!