I saw this (very) long film once on French TV some years ago. I don't really remember the scenes or people in the film, but I can still feel its peculiar atmosphere, imbued with melancholy. I had never been in the US at that point, but I guess this is one of the things that prompted me to get there as soon as I could. It is not exactly a very cheery vision of the US but Kramer does not judge or look down on the people he films, even though they, for some of them, don't share his political leanings. There is no didactic aim in his point of view, just a desire to film and witness an America he believed had changed during his 10-year absence. He's not here to explain but to understand what's going on around him, and the spectator follows in this quest. This is probably one of the greatest documentaries about the US, and it's a real shame that it is still not available in DVD (at least I was unable to find it online), as most Kramer movies it seems.
PS Since this comment, the film has been released in DVD by the French publishing house Montparnasse--it is a beautiful 2 DVD edition plus a CD of music from or inspired by the film. Two thumbs up for this nice job!