There was a lot I liked about this film. In fact, for the first hour or so, I actually felt like a kid again; the action scenes were excellent. There were some wise decisions, like resurrecting Marlon Brando and using John William's brilliant themes. The casting of Kevin Spacey was great, and the comic homages were nice touches.
But in the last half, the film suddenly takes itself much too seriously, and the pacing dropped to be too slow. Why don't filmmakers understand that movies were meant to be 90-120 minutes? Anything over that, and you'd better be friggin' brilliant. There's nothing worse than a guest who overstays his welcome.
The casting was also a problem. For a movie about Superman, he isn't in the film very much, and Brandon Routh doesn't get much of a chance to act (which may very well have been by design). He looks an awful lot like Christopher Reeve; perhaps too much. Kate Bosworth was outright terrible as Lois Lane, and looked awful as a brunette. James Marsden was even worse as her mate. Even Parker Posey, whom I normally like, seemed miscast and looked out of place. Eva Marie Saint looked like she was playing Superman's great-grandmother, but it was still great to see her on the big screen again.
Still, it's worth a rental for the action scenes. Also, this is one of the best sounding films I've heard this year.