This book was nowhere near as good as the first one. The whole war and all the battles felt weird and unnecessary, the whole faction thing felt wholly unexplained (just like in the first one), the "relationship" between Tris and Tobias was boring, and I hated the neuroscientific bits that Roth felt the need to include the mirror neurons and their study of the prefrontal and orbitofrontal cortices). They were really inaccurate and again, weird. 

It kept me just interested enough to give it more than one star and I will read the third one only because I have been assured by colleagues that it is better than the second.