We have one and Cullen very rarely uses it he woud rather walk, in the begining he just didn't like it but now is a bit more use to it and will get on it if you have to get somewhere quickly.
My only concern with having it at WDW is that they will eventually want to just sit down and maybe fall asleep and while it helps with their little legs getting places they will still get tired and I will have to chuck the baby out of his stroller Cullen can have a sleep.
That said we still plan to bring it to WDW
Kirsten