I'm proud that I finally started reading this series (been wanting to since 2013).
Tris' character development is honestly one of my faves, Four (Tobias) is way more romantic in the book, and it was more detailed and emotional. So read this ASAP if you haven't, or only watched the movies!!

[EDITED: 03/30/16] BTW: Please don't be ignorant (like I was at first) and say that this series it a copy of The Hunger Games!! Even though they might share a:
- similar genre (dystopia)
- group people into sections based on their similar characteristics/personalities/backgrounds
- have a young female protagonist
- and the main couple is trying to overthrow the government in some way
The Divergent series still different and unique in its own way. I highly recommend this series, and kind of prefer it more than THG (probably because it seems more realistic, and is less gory and depressing). So please give this series a try!