Its a matter of taste really. I will warn you, its really slow moving. Also the message is really pro-environment. Lol.
The one flaw with this movie, in my mind, is that the moral conflict is too simplified. The main antagonist really is just a caricature. Huge corporation, greedy, evil, manipulative. Environmentalists are altruistic, good, paragons, etc. After the "plot twist", which I did not at all see coming, it becomes way too cliche. Its still a fine movie.