If you're trying to decide whether to see Tron: Legacy, do go. The story is predictable and the characters all color-coded, but that's part of what makes it so enjoyable, like hearing a familiar and well-loved story over again, with new pictures and different voices. It's a good kind of story, about love and duty and becoming a man, understanding what has true value. And visually, it's one of the most gorgeous movies I've seen--that alone would make it worth watching, even if the story was rubbish.
Compared to the original movie, Legacy feels a bit more substantial, less arbitrary, although I must confess that it's been several years since I watched the original, so I may be misrepresenting it. The character motivations are clearer and better developed, although the characters themselves run very close to being simply the predictable stock--hazard of the genre and the necessities of pacing, I suppose.
So: fun, pretty, satisfying. Worth a rewatch or several.