I just thought it was a real cop out to not explain what had happened to the world. In these sort of novels one of the most interesting aspects is why the world is in turmoil. See: The Stand, Children of Men, etc...
I got that it wasn't the point, but I guess I really wanted to know.
At first I found the prose a little pretentious but there was a line early on in the story (I don't remember it but I'll find it later) that pulled me in, and from there on I thought much more highly of the prose. The last 50 pages or so of the book are really thrilling, and I'll confess I was moved.
SPOILER
When the little boy gets sick, that part was really hard!
yr ronin,
joey