I've just finished reading ATGW and I read it in relatively quickly - I can be a fairly slow reader but this novel kept me engaged throughout so I found it easy to power through the story. The whole premise is really interesting - a future world with limited fresh water - and this is established immediately so that we can dive right into that world (no pun intended). There is definitely a sense of secrecy throughout and always a reason to continue onto the next chapter. The central character's thoughts are really delved into and the novel plays with the key idea of morality vs. duty - when do you say no and stand up for what you feel is right and when do you go along with orders out of fear for your own life? The last quarter of the book is especially exciting as we build towards a crucial mission for Enora. Of course things don't work out as we expect and the novel nicely leads us towards a second instalment, ending on a great cliffhanger.
I'd definitely recommend this to fans of the Divergent, Uglies or Hunger Games series.