There's so much one could talk about in Insurgent, but I'll boil it down to what worked so well: the depth of emotion. Whether Tris is involved in action packed savagery or sharing an intimate moment with Tobias, her feelings are on display fully and the reader is experiencing them. Roth's writing brought me into the cell with Tris, making me understand how her split-second decisions worked for or against her, and I found myself unable to put the book down. I love that the relationship between Tris and Tobias is totally real, totally believable, and I love that Tris's intelligence saves her again and again. This is a heroine for the ages; this is a heroine you can believe in and want to be. I love that there is a sad, soft side to Tris, and I love that others hold her accountable for her actions. She's a kick-butt leader with integrity and determination, and right or wrong, she's out to do what's right.
The action is amazing throughout this book, and the character development is phenomenal. Even the secondary characters resonate; no one is fully good or fully bad and histories of relationships can make or break the future. Roth's got me captured completely inside her world and I'm ready for the gates of imagination to open in the final book. Awesome action and credible characters equals one of the best YA series out there now.