Saw Superduperman on Monday. The verdict:

Any scene with Kevin Spacey: TOTALLY AWESOME OMG
The action sequences: TOTALLY AWESOME OMG
The plot: bleh. Thin, and pretty stupid.
Brandon Routh as Superman: Did a decent job. Nothing to write home about.
Whatsherbutt as Lois Lane: Bitchy and irritating. Didn't deserve Superman or Richard.
Cyclops as Richard: Good job on a pretty good character. Richard didn't deserve to have his heart stepped on.
The kid: Annoying, but not as much as people were saying. Also, he doesn't get that much screen time.
3D effects: Kind of random. Some sequences had 3D and some didn't without much rhyme or reason. Sync was a little off but it always is.

If they make sequels, I would like to see some other Superman baddies besides Luthor get in the spotlight. Mr. Myxtlplk probably couldn't carry a whole movie, but Bizarro and Brainiac have potential. Both have possible connections to Luthor (in several of his origins, Bizarro is created by Luthor; Brainiac has teamed up on many occasions). Bizarro can be played for laughs or as a tragic figure. Brainiac is a Class A Asshole in all of his incarnations.