This is a young adult book, so I'm trying to be somewhat lenient on it. That said, I still can't really give it more than a 2 star rating. The concept is interesting, a new planet with new settlers (especially after just finishing Age of Miracles and thinking about what if we needed to escape from Earth) and the chaos that comes out of it. However, it was painful to read.
The suspense was too drawn out (the whole story could have been less than 200 pages, rather than the long fight scenes and unnecessary suspense of the way Ness chose to reveal things).
I also got really tired of Todd's musings. We are all appalled that "to become a man" is to kill someone, but early on Todd is frequently ashamed that he can't kill someone. He is also horribly ashamed that he can't read even though IT WAS OUTLAWED. It is not that he skipped school or is especially stupid. He was prevented from learning to read.
The conversations (especially in the beginning) between Todd and Viola were too dramatic (Really? You'd just leave? he says about 15 minutes after they meet). And he is so worried about carrying the noise-germ, but it is unclear why he would care if he was contagious (after all it turns out that he is the fore-runner of a murdering army too and he seems to have less moral wavering over that).
Any story that chooses to follow "the chosen one" has to be really damn good (Rowling, Tolkien and the Matrix movies mostly pull it off). This was not and I personally just found all the religious references to be too much. After all "even a simpleton knows there's two roads to H(e)aven", but anyone more complex will give up the pursuit of it altogether and just enjoy what they've got.
I half expect that Aaron, Ben and Wilf will return in the sequel. After all, Aaron is the unkillable beast and we didn't see either Ben or Wilf actually die. So we can suspend belief further in pursuit of more fight scenes and drama.
That all said, there were a few decent quotes both of which allude to the title: "The Noise is a main unfiltered, and without a filter, a man is just chaos walking." and "But a knife ain't just a thing, is it? It's a choice, it's something you do. A knife says yes or no, cut or not, die or don't. A knife takes a decision out of your hand and puts it in the world and it never goes back again."
Overall, probably fairly appealing to adolescent boys (lots of violence and some social commentary), better than Hunger Games, but nothing really special.