There are more in depth reviews elsewhere, I have nothing new or interesting to add about the films style, I just want to speak to a couple of criticisms that seem to be common among them.
1. Ruppert discounts human ingenuity.
Having the benefit of the internet and the ability to research, you will find that even generous estimates tell us that any new power grid would take 30 years to establish. This means that if aliens came down to earth and gave us a perfect technology that required no input and had zero emissions it would still require a lot of oil and time to build an infrastructure to support it. The fact is oil has artificially increased our carrying capacity and when its gone, the excess population will go with it. The standard of living we all have come to demand will likely never return and certainly not for 7+ billion people. (not that we all have Hummers and flat screens now)
2. The San Francisco (chronicle?) lauds the moment Ruppert cries because they think he is lamenting the fate of humanity.
I think it's highly likely, and more compelling to look at the beginning of the documentary where he says he's lost his fiancé to betrayal and only has his dog, the beach, and this movement to get him by. He's crying because he thinks it will take a community to survive in the aftermath of the collapse, and he has no loved ones.