I agree that they are two very different parks. My 15 y/o son will not go to WDW but will fly in for US/IoA. Last year I went with my mom and DD to WDW for 12 days. At the end we transferred over to HRH and my DH and DS flew in and stayed 5 days there with us. My youngest DD, then 3, loved Curious George, Seussland, the Animal Planet show and Fievel. We had bought APs for US/IoA last year because they were such a great bargain, cheaper then a 5 day two park ticket. Since they will still be good for my upcoming WDW trip in October we will be going over to US/IoA for the day to do all the kiddie rides I mentioned and also to go on Spiderman. We loved Spiderman and wish WDW would do something similar. While I would not make a special trek to see US, it is nice to have it there for something extra when going to WDW.