I liked the movie version of Hair, but couldn't really love it...I'll probably have to watch it again sometime.
I think one of the problems I had with it is that it just felt so 1979 to me--you could tell it was made a decade after the original stage production, at a time when all the urgency of the issues addressed in the musical was gone. This is probably how the movie version of Rent is going to be seen a few years down the road. That the two films were both made when the material was already "dated" is not necessarily a bad thing--it gives both movies a sort of wisdom about the subject matter, as if the filmmakers were looking back and turning the movie into a love letter to the previous decade--but both Hair and Rent were originally such visceral, from-the-gut, in-the-moment stage productions that there's bound to be something lost when you translate the material to film 10 years later. Both movies have their moments that remind you of the original productions with their wild anger and intensity, but neither one feels completely like you're getting the real deal.
The character development in the movie version of Rent makes it a stronger movie musical in my eyes than Hair--you feel such a strong bond between the cast members that you feel like you're watching a real group of friends (which, really, you are), and in turn the whole begins to feel more like a real product of the 1990s/1980s (although it never quite gets there). I can honestly say, though, that I really didn't feel much for the characters in the movie version of Hair, and so that led me to be even more distracted by the fact that the movie overall didn't feel authentically 1960s.
In any case, like I said, I need to watch Hair again. I did enjoy it, I just didn't feel it.
"If there is going to be a restoration fee, there should also be a Renaissance fee, a Middle Ages fee and a Dark Ages fee. Someone must have men in the back room making up names, euphemisms for profit."
(Emanuel Azenberg)