While visually awesome (I especially liked night scenes), I thought the story and dialogue was very very mediocre.
I'd have to agree with this.
We saw it in 2-D because it wasn't playing in 3-D or IMAX on the day we had time to go (yesterday).
I thought the visuals and the idea behind the world itself were great. There were some minor things I might change, but still it was well crafted. But the story itself and dialog was mediocre. I wanted it to be more complex.
Also, I would have liked it better if it wasn't a war movie. A more thoughtful resolution to the fight would have worked better, in my opinion. They kind of set it up that way (in my mind at least) so I was a bit disappointed that they didn't follow through.
I thought the acting for the alien characters was really good, especially the main girl character. You could really sense the emotions on their faces (don't know if that was the actors, the CGI or both). The human acting was fine, too.
Overall, the visuals, even in 2-D, and the interesting premise were bigger factors than the mediocre story and dialog, so I give it 8/10.