I traveled to Orlando in June, 2012 with my family to visit Universal and some other attractions. I'm not a fan of Harry Potter, but the mock-up they had at Universal was perhaps one of the best attractions I've ever seen. Universal landed a good one with this popular theme, and they went out of their way to create an authentic park--right down to the English employees with authentic Hogwartsesque accents.
Yes, it was crowded. My daughter and I waited for an hour and a half to see the presentation at "Olivander's" and I think she was under the impression that every kid would get to interact with the "shopkeeper." This was not the case--they only pick one child to participate in the show. It was worth the wait to see the inside of the store, though.
The best part, though, was the Harry Potter ride itself. I don't usually say this, but dude--I thought I was in the movie. Nice effects, and the decor was once again authentic. The wait was long--an hour and a half--but the ride was worth it.
There is a deal you can get if you stay at one of the Universal hotels that lets you in an hour early to the Harry Potter Ride (Wizarding World). However, you may want to check that hotel price to decide if it's worth it.
All in all, take the time, wait in the line and check this place out. Even if you're not a fan, it's worth it. If you are a fan, then you will love this place.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.