Great visuals, poor storyline and writing. It seems 13 years weren't enough for Cameron to improve a single line of the dialogues. Tons of cliches. Tons of plot conveniences and plot holes, like where were the Metkayina when Jake and Neytiri went to rescue their family? What was the dynamics in the relationship between Quaritch and Spider to understand their motivations and decisions at the end? It's not even clear the motivations of Quaritch to hunt Sully to begin with. Some may say that these and other holes are due to a cut Cameron had to do to the original 3 and a half hours movie length, but that's not a valid pretext as he could've cut some parts from the long and dull set up in the first hour. Besides, it's not like Cameron is an independent filmaker that was victim of a big studio decisions, he has full control over the final product.

Overall it's a mediocre movie with great visuals and packed action. If you aren't a fan of the 3D experience and have a big screen at home, just wait and see it at home some rainy Sunday when you feel like turning your brain off for a couple of hours.