Umm, with the age of this thread, their kids are 11, 13, and 17 by now. Although I would love to hear if their kids still enjoy the parks but the OP hasnt been seen since 2013....OP, I think the 11 y/o will love it. There is so much to see and do, and not all of it is for little children.
Of course, the 5 and 7 y/o's will love it too.
My husband and I are in our 70's and we never get tired of it.
I do think some teenagers lose interest but then it comes back when they are adults.