I went to see Superman Returns at the local megamulticineplex last night. Thanks to tips from others in the blogosphere, I knew ahead of time that it takes place after Superman II, making it much more logical. It also helps me forget that Superman III and IV ever existed.
It is definitely worth seeing even though it is, as others have commented, a little too long.
Kevin Spacey was great as Lex Luthor, playing the character less as a comedic bad guy and more as the megalomaniac villain with a heart of kryptonite.
Brandon Routh did evoke images of Christopher Reeve, though the affected clumsiness wasn't nearly as evident as in Reeve's portrayal of Clark Kent/Superman.
One scene that surprised me was seeing the same portrayal of the Kent farm in Kansas, though I don't know if it was the actual location or a recreation of the original.
All in all, I liked it.