My boys (a mature 8 and a not-so-mature 6) are completely psyched to see it, but when I read the IMDB parents guide, I was a little leery. The KIM guide actually eased my mind a little bit about it; they've both seen Batman Begins, which is a 2.6.3, and they were fine with it.
The Dark Knight and The Dark Knight Rises will definitely wait a few more years, though.