Trisha and Alix have already posted their thoughts below, I'm posting just one part about the book that I found interesting.
Not only does the book explore rules and the power of individual choice, it also delves in to love and relationships. Cassia feels torn because by questioning the Society she questions everything her life has been based on. If she questions her Match, what does that mean about her parents? From page 221 (in the advance review copy, may change at publication):
"But if the system is wrong and false and unreal, then what about the love between my parents? If their love was born because of the Society, can it still be real and good and right? This is the question that I can't get out of my mind. I want the answer to be yes. That their love is true. I want it to have beauty and reality independent of anything else."The Matching system, to me, seemed somewhat like arranged marriages. Only arranged marriages where our parents knew every little thing about us and about the other person and made a choice based on our genes and actions and future thoughts, all of which they have predicted out with a fair amount of certainty. Just because someone else has decided for you, does that make it less so? Can love blossom in such a scenario?
For more thoughts (and discussion, in the comments) and a chance to win the book, check out my full review here.