It's difficult to discuss Metropolis without first establishing which version of the film people have seen. Since there are public domain, and copyrighted titles out there, and virtually all with footage missing, reordered, reinserted, or reinserted as stills, not to mention a dozens of different soundtracks and stuff...
That said -
I was fortunate enough to see the mid or late 1980's Georgio Moroder rerelease in the theater which restored several minutes of footage, tinting, some stills, and a new score featuring some metsa-metsa pop tunes along with the visuals. I absolutely loved every minute of it.
I've also seen some of the cheapy releases on VHS and DVD with various piano scores and/or stock soundtracks. I am guessing the restored version linked above is probably closest to Lang's original, but even then I can't say for sure. The story has always stuck with me though, and I loved the dichotomy of the workers and leisure/management classes and how when finally exposed to just how dire the situation below the city is, Freder becomes a reformer even as his father is hatching a plan to lead the workers into a suicidal rebellion.
Lang's camerawork, especially stuff like attaching a camera directly to the cameraman and swinging him at Freder to simulate an explosion, is fantastic. The miniatures never seem to feel like a scale city, and even film like Things to Come (which I also love) don't manage to look as convincing as Metropolis does.
Just can't say enough good things about this film. Today much of the moralizing in it will look ham handed, but I think remembering that it was produced in 1927 at the height of the industrial revolution when Germany was all but bankrupt, helps keep it in perspective.
For science fiction on film, it doesn't get much better than Metropolis.
And for crime drama, Lang's "M", the film that introduced Peter Lorre to film, is the best crime drama ever made.
