Hmmm. Overall, not too bad. Could have been a LOT worse. Of course, I have issues with CG animation to start with (I just don't like 3D computer stuff. I prefer the old 2D animation, myself), and I couldn't help but notice that while the detail was near-perfect (you could discern individual strands of hair!) there was some issues still necessary to attend to in the movement of the people - noticeably in the face. Many of the facial muscles were apparently 'left out', leaving the skin looking 'tight' and immobile. Human faces tend to be rather loose and stretchy. This meant that the characters had no extreme expressions - when the main character cried, she looked like she had a deadpan expression. The same when she was greatly distraught or angry. That just bugged me... maybe because even in much simplified 2D animation, expressions can be made very, very clear, and they were not in this movie.
As for the plot and dialogue, again, could have been worse. The story seemed as though the writers apparently thought it was a bit more interesting than it actually is. The voice acting was miraculously good, though it was rather foiled by the lack of facial expression. The action was a little slow most of the time, and was interrupted by damned annoying character development that never really did much other than rely on easily-quotable wisecracks and stock attitudes to define individual people.
Overall, it was worth seeing just to get a glimpse of how far computer animation has come - and to see what still needs to be done. But I wouldn't see it again... and I doubt I'd advise that most people see it.