We did it last month after waiting years for Matt to be old enough, he has been wanting to do it since he was about 12.
We know a lot of Disney trivia and we have a friend in security at MK so knew quite a lot of what we were told, even so it was well worth doing. You don't get to see too much but again enough to be worth doing. One thing really cool was down in the Utilidors the framed pins what looked to be from day 1, loads of them there and the pin replenishment station where CM's go for new ones. Old pictures and photos on the walls. Nowhere near enough time to get a good look but you get a glimpse of the history.
You get to eat lunch at Harbour House upstairs where its quiet(roped off)
Not cheap (what is in Disney?) but not OTT at about $75pp, I did see on that link when I just looked
AAA discounts available, I never asked