Last year when we went to US and IOA my kids were 10 and 4. My DD (10) loved the parks and does not want to go back to Disney!! My DS (4) had a ball and keeps asking when we are going back. He esp. loved Seuss Landing (awesome) and seeing the Justice League guys (we have great photos of him with Spiderman etc.). Even though he had never been a Barney fan, he really enjoyed the show at Universal. The Jimmy Neutron ride is great for younger kids and so is ET's Adventure, MIB, Etc. There are many playgrounds at both parks. There are TONS of characters around the parks including Nickelodeon characters, Scooby and Shaggy, and many others. My DD rode every ride in both parks. Many of the restaurants at the Citywalk area are very kid friendly and a lot of fun ( my guys liked NBA City and NASCAR Cafe). I think your kids will have a great time. We stayed at RPR last year-they loved the pool. We are going to HRH this year.