The effects alone are a great reason to see this movie. The animation in this movie is so lifelike that I found myself drifting from the animated characters to the real seamlessly. It's especially good in 3D
That said, the plot was boring formula. The bad guys are bad people, the natives are noble savages, ho hum.
I would ask all parents to strongly consider not taking their younger kids to the movie. I took my 9-year old based on the MPAA rating of PG-13 for "intense epic battle sequences and warfare", but I would say the rating of R for "graphic violence" would be more appropriate. There are several examples in the movie of personal killing, spears embedded in bodies, etc.