Do you have park-to-park tickets, and do you plan on visiting volcano bay?
On my last trip i spent 4 days in the parks. Spent one full day in each then the other two days were spent revisiting highlights, relaxing at the pool, and enjoying a couple of sit-down restaurants, etc.
The express passes should make it easy enough to hit pretty much all of the rides you want within each park. If spent one day per park then your third day going back and re-riding or catching anything you didn't fit in.
I (like many folks who enjoy universal) am a harry potter fan. I prioritized those rides on my first day in each park (+ early entry will help), then on my "extra days" i went back and did the themed areas a little slower to enjoy the ambiance. Eating at 3 Broomsticks is also fun. Food isn't amazing, but the theming is A+ and worth it.
I guess it kinda depends on your priorities and likes/dislikes? The boats to the park gates is a huge perk of staying at Portofino!