This was an interesting movie. Apparently the concert was filmed but never seen, kind of like the Aretha Franklin concert movie, Amazing Grace. It was a fundraiser for Huntington's disease research three years after Guthrie died from the disease.
Some now-forgotten folks from 1970, such as Country Joe McDonald and Ramblin' Jack Elliott, handle the material well. I have always liked Joan Baez's rendition of Deportees, but I can't for the life of me understand why she purposefully mispronounces the Spanish word "y." She says something that sounds like "a." Comes off as pretentious.