Some parts of it are good, some parts are dreadful. Pretty much all of it is visually spectacular, but I wish Lucas had sacrificed some of the digital gimmickry for…well, a better screenwriter.
The dialogue was a step up from Episode II, but that’s not saying much. The action is astonishing, but the key thing that sank it for me was Anakin’s relationship with Padme. It is cool, and devoid of passion. Sure, they talk about love, but there are no scenes that elaborate on how deep this runs. And without this depth, Anakin’s journey to the Dark Side doesn’t ring true enough. I can see these characters acting out their inevitable destiny, but I don’t believe it.
The traditional rule of storytelling is “show, don’t tell.” Lucas falls foul of this rule too often in Sith for the film to work on an emotional level–unless you have so much personal dedication to the saga that you can supply it for yourself.
Ultimately, though, I’m not even sure if the story of Anakin’s fall from grace is a story that should have been shown at all. The story of Star Wars is Luke Skywalker’s battle with his father in Episodes IV – VI: a struggle between good and evil, with good ultimately triumphant. Episodes I-III are the back story for the main feature. There is a long, twisty tale there of love and betrayal, but with a legend that big, you can do two things: sum it up in a a few sentences, leaving the audience’s mind to fill in the details, or spin it out into somehing that is long enough to deal with the subtleties of the material.
Interestingly, it is Episode I that now stands out for me as the best of the first three films, because it is the least involved with Anakin’s tortuous journey. It can be seen as a stand-alone prologue, introducing the universe and the forces of light and darkness, and it has a nicely self-contained plot, with a satisfying climax. Episodes II and III rely far too much on their nudge-nudge, wink-wink hooks into subsequent episodes to be decent films in their own right.
So: points for wrapping the story up at last, so we can all get on with our lives. Points subtracted for it being–in anything other than its own context–a rather poor film.