Are you going to be visiting the Universal Orlando parks?
Are you getting two rooms?
They are both wonderful resorts. The Portofino is more spread out and is not as convenient for getting to the parks. There are water taxis and a bus at each place to get you to the parks, but the Royal Pacific is a very easy walk to City Walk and the parks.
The rooms at Portofino are bigger and the atmosphere is more quiet although the Royal is far from a noisy place.
Of the three on site resorts at Universal, the Royal Pacific is my favorite. I love the decor, the atmosphere and the proximity to the parks. The beds are SOOOOO comfortable!

Have not stayed at the Royal Pacific. I have stayed at the Portofino and the Hard Rock. The tiering on these hotels is as follows:

Portofino Bay (PB) - high end
Hard Rock (HR) - mid
Royal Pacific (RP) - lower end

Of the 2 I prefer the HR because of the great pool area and proximity to park and citywalk (easy walk). The PB is more luxurious and relaxing but you must take the boat or bus to the parks and citywalk. Can't really comment on the RP except to say that Emeril has a restaurant there (TchoupTchoup). Some say that the HR is to noisy but I did not notice that. The PB has a really nice "feel" to it and it doesn't seem that you are in the middle of a theme park. It is really nice to sit out on the piazza(sp) overlooking the bay in the evening with a bottle of wine..... I remember when they were building the PB that it was supposed to be Orlando's first 5 star hotel (don't think that they quite achieved that but it is quite nice). I remember sitting by the quiet pool at PB and the waiter would bring around fruit kabobs and cucumber slices to put on your eyes if you like that sort of thing. Enjoy!!

I LOVE the Portofino, so that would be my choice.

We usually use the water taxi, but there is a shortcut through the Hard Rock parking lot, making the walk shorter than the suggested walk trail provided.

We've had a few meals at the Royal Pacific and was struck by the number of people waiting to board the water taxi at the resort, not something I've ever found at Portofino. I guess it has to do with The Portofino's 750 guest rooms compared to 1000 @ the Royal Pacific.

I believe standard rooms are just over 100 sq ft larger at Portofino which might matter to you if you're all sharing one room.

Which ever you choose, you'll be receiving the best perk of all IMO; Universal Express ride access.

Thank you for the input everyone. Although my preference would be the Portofino my daughter's have chosen the Royal Pacific.

I have stayed at both hotels more than once. You cannot make a mistake. Both are beautiful. Have fun!