If you have one-day tickets, IMHO , IOA is best for young kids if you have to pick one.If you're using one day of a multi-day ticket, and can park hop, you may have time(depending on the time of year) to do IOA and then hop over to USand do ET, Fievelplay area,Animal Actors show,and the other couple of kids things, can't remember them as mine are older now.Don't miss Seussland at IOA though, it's truly a Dr Seuss book come to life!!