I haven't yet because it mirrors the life of a friend from school and I think it would upset me. But another friend read it and thought it was one of the best books she's read.
It's essentially Dave Eggers telling the story of his young life. Losing both his parents to illness, moving to California, raising his younger brother and becoming a writer. Sometimes he rambles a little bit, but lots of great stories along the way.
I had to read it in high school, it wasn't really my style... but I do know a lot of people who loved it. It's a very unique story, but quite depressing.