This is the sort of animated film that (thank goodness) doesn't undermine an adult's intelligence. Without resorting to schmaltz, it generates genuine emotion. And best of all it nicely balances Sci-Fi/Fantasy with believability.
I would actually go so far as to say that this picture had a heart about the size of its title character. I have rarely seen a kids' animated film pack such an emotional wallop as "The Iron Giant" did.
From my perspective, this film didn't appear to contain a single bum-note or wasted scene. It was funny. It was exhilarating. And its graphics, that blends hand-drawn, 2-D animation with CG imagery, were a sheer delight to the eyes.
It's interesting to note that this film was a literal box-office failure upon its initial release back in 1999. This was clearly the fault of Warner Bros. who simply didn't realize what a sparkling, little diamond that they held in their hand.