Thats a tough one. 8 huh? I would have to say it depends on your kid. How tall is he? Would he be horribly disappointed if he had to pass up some rides because he isnt tall enough? When my son was 8 he couldnt ride hulk or dragons, and was too scared to ride jurassic park at IOA, but was able to ride everything at Universal. Its a totally different type of park than disney, and 8 is such an in-between age, I'd concentrate on US and make sure he knew whether or not he was able to ride the coasters ahead of time. But I'm sure he would love Spiderman and all the wet rides at IOA.