Superman Returns ... 6.5/10.
I hadn't seen this in years -- though I've heard people complain about it a lot since then. It wasn't as bad as I recall. It is watchable. It is a complete failure as an attempted reboot. But, it actually works fairly well as an ending to the Donner trilogy ... Superman: The Movie; Superman II Donner Cut; Superman Returns.
There were some cool scenes in there -- the plane crash, the car catch, the Daily Planet globe. The suit looked great. The casting was great, with one notable exception. I liked Routh's Superman and Clark Kent ... though he was asked to do too much of a Reeve imitation to really make anything of it. Spacey's Lex Luthor was a little over-the-top on occasion ... still not sinister enough ... but a LOT better than Hackman. He's still no Rosenbaum. The side parts -- Perry White, Jimmy Olsen, Richard White, Miss Tessmacher (or whatever her name was in this) -- were all well cast.
The low points ...
The script wasn't very good at all. It seemed like Singer spent a lot of time thinking about the physics of flight, casting, the look of the costume, homages to Donner, and the overall ambiance of the movie ... and almost no time thinking about finding a story worth telling, or considering that he was making Superman into a weird jilted lover.
Lex Luthor's plan is stupid from top-to-bottom. Luthor is supposed to be a mastermind ... not Brain from Pinky and the Brain. The illegitimate son/ Superman-is-a-deadbeat-dad plotline was poorly conceived, and has no place in a Superman movie. And, they didn't even think ahead ... where do you go in a sequel? Superman's son sidekick? Kill him off and send Superman on a revenge quest? Complete mess.
Lois Lane is really the only casting trainwreck. Too young, and she can't act.
There are enough high points to make this watchable if you consider it closure to the Donner movies rather than a failed reboot attempt. As a reboot ... it is too Donner-dependent. As an end to the trilogy ... it fits well enough.
SnakeDoc