So I'm reading this series for the second time along with my ten year old, and there is just so much that Collins gets right in this first book of the series. Gregor is a great everyman hero, and his love for his little sister is spot-on. Collins gets sibling love. I found the world building much more believable than in the Hunger Games books. This is definitely the lightest book in the series. Good and evil are pretty unmuddled. Man, by books 3 and 4, it's getting so much more philosophical. Book 5 is dark and tough. I'm not sure my son will really be up for 4 and 5 yet. But I appreciate that this series shows the horrors of war and doesn't have easy answers. Sometimes it's the right thing to fight to protect the innocent, but just war theory gets really complicated really fast. And I don't think she does any of it in a preachy way. 
 As a book taken on its own merits, this one has some nice closure but does a good job of leaving room for the further adventures.