In short, it's not worth the price of admission. If you really want to know why, then by all means read on. I just didn't want you to waste any more time on this movie than necessary.
I mean, don't get me wrong, this isn't a bad movie. It's just that there's nothing good in it. From start to finish, it's as bland and predictable as a Disney movie can possibly be. You probably already know the whole plot already, or else you could make an educated guess.
The acting is wooden and unbelievable, the narrative is riddled with gaping, obvious plot holes, and the villain is laughably destructive, killing underlings and civilians without warning or mercy, even when it would be in his better interests NOT to kill them.
The good guys are equally unlikeable. Kevin Flynn, the protagonist's Zen-Master/Wizard/Hacker father, never expresses any believable remorse for missing out on twenty years of his son's life. That son, Sam, immediately forgives his father upon learning why he disappeared one night when he was seven, never to be heard from again. Hey, no hard feelings, right? We cool? Yeah, we're cool.
The love-interest, Quorra, lacks even a rudimentary pesonality - she alludes to being less patient that her mentor, but this quality is never demonstrated onscreen. I'd call her eye-candy, but it's a kids' movie, so there's not even enough skin to make her any more appealing visually than she is emotionally. But this doesn't stop Sam from falling for her the moment she bursts right into the Games Arena in a transforming off-road vehicle (no joke!) to save his sorry ass, even though she's never seen him before.
It might, might, be worth the price of admission, if you're:
A) a kid under the age of eight,
B) a CGI-fanatic, or
C) such an enormous fan of the franchise that it's starting to damage your social life.
If none of these terms could be applied to you, then just save your money.
ADDENDUM: There was one bit that I thought was clever. When Sam and Quorra go to the dance club (yes, really!), the event is DJ-ed by two helmeted men who look suspiciously like an homage to the French techno-duo Daft Punk.
... that's it. The only part of the whole movie that was clever or (intentionally) funny.