Strengths: Outstanding effects, 3D that's worth the price of admission, being able to take breaks from 3D for the 2D scenes, excellent action sequences, solid story, consistently entertaining, sympathetic main character (Sam Flynn), the TRON world still existing in an 80s motif, Olivia Wilde wearing a skintight outfit
Weaknesses: Predictable moments, relying on the audience's familiarity with the original (not that you NEED to see the original to understand what's going on, but it's recommended if you're going to fully appreciate certain aspects), reverse aging of Kevin Flynn is obviously done digitally (a minor gripe perhaps, but it occasionally bugged me). I also disliked a couple of visual presentation decisions (the pixellated-looking flashbacks did nothing to enhance those scenes), but that may be a personal taste complaint only.
Verdict: Go (re)watch TRON, and if you (still) enjoy it definitely watch this one and you'll enjoy it as well. I thought the pacing was better and obviously the effects have improved thanks to the difference of time & technology. There's room for improvement here (less reliance on familiarity with the first, better character development), but overall it's an entertaining film worth watching.
7/10