Bakshi's ambitious attempt to capture the history of American pop music in a single film, using four generations of a single family to guide us through it. On the one hand it's a pretty impressive undertaking that deserves praise, on the other hand it was so excruciatingly boring that it's hard for me to say anything overtly positive about this film.
It's probably a lot more interesting for people with an active interest in American (pop) history/culture. Personally I don't care much either. The music is terrible, other historical references have been done so many times before that I really didn't have to see them summarized again.
The animation is pretty interesting, but the art style is ugly. Characters are dull, the background art is lifeless and the film is at least 45 minutes too long. It saddens me to say this about an animated film from the US that isn't squarely aimed at kids, but this pandering to the past is just too damn tiring.