My 5-year-old and I saw it on Wednesday. It's cute, but wasn't an instant favorite. We didn't like the 3-D either. There were a couple of plot twists that seemed a little complex for younger kids, but overall it was an enjoyable movie. It's Disney - there's always a dark tone lurking in the storyline, they're way too focused on how the girl looks, there always has to be a "prince" involved, etc. You have to take it all with a grain (or two) of salt and try to neutralize some of the crazier ideas after viewing. When we see a movie that is based on a book, we always discuss the differences in each, and which story or parts we like more.
Rapunzel in the movie took a lot more risks and was way more outspoken than Cinderella, Snow White or Aurora. But I felt like she was still pretty dependent on the man (although being locked in a tower for 18 years may be a pretty good excuse for that!), and in the end, even though she made a big decision on her own, the man ended up "saving" her (hope that doesn't give away too much for those who haven't seen it!).