I recommend it. Really.
Despite the very odd context, I think it's right up there as a "good superhero movie" next to Spiderman. Fun animation, good story telling, good storyboarding, good direction, good plot, good characters who develop naturally from their motivations.
And for people with a secret taste for "thrilling superpowered fight scenes", the "tag game" sequence has both the Superman II "fight in Metropolis" and anything on "Dragonball Z" beat all hollow.
I was easily by a factor of two the oldest ticket holder in the theater.