I picked this up on a trip to the US and was disturbed by two things.
Firstly, it is simply the most disturbing and violent book content wise that I read in a long time.
Secondly, there is a lot of Spanish in this book and I get that many people in the US speak at least some Spanish, but none of the six languages that I speak is Spanish. I managed, guessing most of it with reference to my French, but I would only recommend this book to people who speak English and Spanish. 
So, both of these disturbing things are not negatives, just things a reader should be aware of.

I saw the ending coming, hoped it wouldn't, and was still shocked when it happened. I works as a grim metaphor the inescapable marks of poverty.