I just want to agree with what the other posters here said. When we went a year and a half ago, my two younger sons (then ages almost 4 and 7-and-a-half), both LOVED both parks! My older son loved MIB and BTTF, the younger one loved ET and the play areas, both loved Jurrasic Park at IOA, Dr. Seuss, SpiderMan. All three of my kids loved watching the huge slime fountain erupt outside Nickelodeon studios, and since they're huge Nick fans, they were thrilled just to be there. These are both just great parks for kids this age (and also have plenty for older kids too)! I also agree with the advice about bringing some dry clothes; you can get very wet at these parks. (Oh, almost forgot, I don't even know if this attraction is still open, but my 7-year-old freaked on Twister at Universal. Wow. Very loud and very intense and he did NOT enjoy it. On the other hand, my then-10-year-old loved it and did it three times. Just a word of warning if your kids are sensitive to things like that).