I liked that movie. I love Crumb's artwork - more for style than content, but that dude has some serious issues. The doc was definitely interesting, tho.
You should watch American Splendor. It's not a documentary - Paul Giamatti plays Harvey Pekar, who wrote some mostly autobiographical comics (he didn't illustrate) that were called American Splendor. He was a bit off center, to say the least. Very interesting, IMO.