I have watched part of it (no time for more right now). It seems interesting and realistic on many issues (UV problem for exemple). Actually, I have recently found an article stating that even a limited nuclear war would have harsh global consequences on UV levels. Definitely, it's well made and I find interesting that it was made just after a time when people had feared from something like that. I think that it was in 1982 when my parents made food reserves as they were fearing for war. However, I'm not convinced by everything.
Concerning harvest the lack of chemicals seems to be rated first and I'm not sure that would be a problem. In fact, we already put so much into the ground than that might not be a problem at all. From what I know the Amish in US are gettting the best crop output while they are not using any chemicals. Insects and drought could well be a problem, however. Finding seeds might be another problem.
They depict a society with no rules and where no one has taken over. I find that highly unbelievable especially as they compare the figures to that of the Middle Ages. They forgot, that most European societies had been built around bandits who had settled down and carved their own petty kingdoms. Most often, being part of the nobility means that one of your ancester was some kind of bandits who made his fortune using ways similar to that of the modern mafias. In that matter, I find the ideas of T2K more realistic.
One more thing, the world (humanity) already survived to the level of casualties that would bring a nuclear war and I would not be surprised if it was to survive again. The Great Plague (1347-1350) had killed to a similar level and that combined with severe hunger and global freezing. I'm sure that we would face new problems but what occur at that time is interesting to imagine what could happen after a nuclear conflict. Here is the link to the Wiki on it. It might inerest you.
http://en.wikipedia.org/wiki/Black_Death