I went to see this documentary by Jennifer Baichwal yesterday and while I liked it a lot, I should warn potential filmgoers that the marketing is a bit misleading. The previews I'd seen, at least, led some people to expect a seriously political film about environmental problems in China. The film really doesn't give you the kind of essayistic argument that you see in SiCKO and An Inconvenient Truth. Instead of being a political movie about environmental problems in China, it's an arty movie about Edward Burtynsky's still photographs of industrial processes and the landscapes that result from them in China.
Personally, I appreciated the non-didactic tone. The film's hints as to the filmmakers' political views made me think I'd be considerably more enthusiastic about China's economic rise than they are, but the movie mostly plays it straight. The takeaway point becomes not something about what must be done or the technical origins of the problems (you should probably read Christina Larson's article about China and the environment for that), but rather something about the sheer scale of what's happening. The combination of film and still photography does an excellent job of driving home exactly how much is changing how rapidly over there in a way that the brute numbers can't quite convey.
UPDATE: Or see Dana Goldstein's essentially identical review.