When you enter the great hall, it is just as you expect it to be, Once you are through the great hall, you are on your own to visit the wonder that is Harry Potter. Children will just want to explore but there are also audio/visual guides you can pick up before you start the tour, which has extra information. I loved this feature, as it was interviews with all the creators and people who worked behind the scenes. I wish they would have compiled this onto a DVD, because I would have purchased that. The kids are given "passports" which they stamp themselves when they find where they are supposed to go. The details that was put into the making of these films is beyone impressive, for instance the myriad of potions or the diversity of the wands. You find out about the animals used in the movies, and how the dementors achieve their creepiness. You can fly on a broom, (and pay for the picture after.) There is a gift shop at the end, which others have mentioned is pricey. They do not accept the Maestro card.
We took one of the many tour buses that are available. It takes over an hour to get there from London. That is the easiest way to go. That means you have a set amount of time you can stay but they timed it pretty well. I don't think one is better than another, but be sure to get there early if you have kids who will want to sit on top of the double decker bus. We got there 20 minuutes early and were on the bottom. It is, however, just a bus ride so sitting on the bottom is not the end of the world.
Even if you were not the biggest fan of the books or movies, you cannot help but appreciate the amount of thought and effort that was put into these films. And if you are a fan, you will be blown away.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC