Saw this yesterday afternoon and yes it's a five star classic. A concert movie where you'll have a different favourite performance every time you watch. The brief glimpse of Sonny Sharrock inventing Sonic Youth has stuck with me, but there's amazing Stevie, Sly, Mahalia, Mavis, Nina performances too - in the case of the former you're watching Stevie reinvent himself (stick to the end of the credits for a nice gag bit by Mr Wonder). And you'll want to get up on stage and join in with The Fifth Dimension. BBFC title/censor card warns that you will see 'dead bodies', and you do, in a fierce, revolutionary film.