I kind of figured going into the movie that my 6-yard old daughter would love this movie since she's like the first two, and that I wouldn't.
And that's about how it worked out. She laughed, was interested in the story, figured out what was good, what was bad, etc...
Me on the other hand, got more joy out of watching her laugh since I couldn't really find anything to laugh about myself. For the adult, it's a little slow, by the time the "switch" happens, the movies 3/4 of the way over.
But hey, if you thought it would be good going into it, you're probably on a different level from me anyway. But, the kids will like it, and that's why we go, I guess.