OH WOW. 
 I actually loved the ending! (view spoiler)[I completely hate when they resuscitate characters and was glad it was not the case (hide spoiler)] 
 One thing with this book is that I could not see at all where the story was going, and the outside surprised me a lot. I felt like the GAs and the Purity Wars could be explained better, because at times they didn't make sense at all (half the population gone, why the war really started, how the GAs really affected a person and etc) But the ending kind of made up for me, It was the only part of the book that got me REALLY excited. 
 I just finished reading and am still felling giddy and excited so that might explain the high rating (view spoiler)[giving 5 starts to a book which part I most liked was when the main character gets killed seems rather suspicious (hide spoiler)]...