My kid is super into Harry Potter; she's read the fifth book so many times, the binding fell apart. She has excellent reading skills, and I first found that out when watching one of the movies and she was bummed because "so-and-so had a red beard in the books, and a black one in the movie!". Like the OP, when she finished the books, we agreed to take her to Orlando. It was about a week or so after opening, so it was crowded, and I had ZERO f-----g interest in it at that time, and two things happened: my kid had an experience that she STILL talks about, and I got introduced to a really cool world. We've been back I think three times now, and in the interim I read all 7 books and saw all 8 movies, and all I can say is, if you suspend the cynism, it's a really fun time. I've stood in line as long as two hours for the ride at the bank (I can't remember my kids' names let alone the ride names) and it was worth it. Seeing the castle up on the hill is breathtaking. Riding the Hogwart's Express (that wasn't there the first time) is very cool.
Honestly? The worst thing about the whole package... the other tourists. People are just dicks, man. Across the board.