Although DH and I often stay-offsite, I'd recommend you stay on-site, since it will be your first time.
Also, although we have never stayed at HIFS, on a recent trip, we visited for the seafood buffet, which was very good, BTW, as well as the service.
What we could not help but notice, however, was that the place was over run with children
... mostly the ill-behaved type
Of course, you can find that experience anywhere, but it was particularly prevalent at HIFS.
Now, that may not be an issue for you, since you have a son of your own. However, if he is well-behaved, and you do not want to deal with alot of other peoples' children on your vacation, then you may want to reconsider.
Then again, the week you go, you may not encounter what I described above at all. The place does seem to be geared more to younger children (those of your son's age). I just thought you should hear the flip side. Several times during our meal, I said to my DH, "Nice place to visit, but I wouldn't want to stay here." or "Boy, I'm glad we're not staying here."
