My wife and I were both bowled over by the quality of this movie -- characters, cgi and 3D. After a few establishment scenes, the action begins and simply does not let up until the ending credits.
Everyone has seen at least one variation on this particular plot, such as Dances With Wolves. Still, it was very well done.
We were both particularly impressed with the quality of the 3D effect. Nothing like the 3D from the 20th century. My only "complaint", and its a small one, is that I initially felt as though my eyes were crossing. Once my eyes learned how to adapt to it, no further difficulties.