This is a spoiler-free review. You can find this, and more reviews from me, on my blog thisisjustabookblog.tumblr.com 
 I pre-ordered this book, so it arrived by the end of October. It's been sitting on my shelf since then, begging me to read it. I didn't really have time, what with coursework, because I also wanted to re-read the first two before getting into this. 
 Then, after reading the first two, I put off this one for another couple of weeks, because I love these books. I love the characters and the world and Roth's writing and I was so nervous about Allegiant. I was nervous that I wouldn't like it or all my favourite characters would die or it wouldn't live up to my expectations. 
 Well, let me tell you: Allegiant is devastating. I cried through the last 50 pages or something, and then a little after I finished the book. Though I wasn't pulled right into the book from the very beginning, the second half of the book definitely lived up to my expectations. 
 I think my main problem with the novel is that it is very slow-paced for the vast majority of it. I read half of the book last night, and managed to put it down and go to bed at a reasonable time because I just didn't feel caught up in it. It didn't feel like much was happening. 
 But the second half, which I read the next morning was 100% better. The action started, it picked up the pace, I started to like the characters more. 
 I definitely disagreed with a lot of things Tris and Tobias did towards each other for the first half of the novel, and I felt that it was a little bit contrived; like Roth was purposely putting things in their way to keep them apart, to add more drama to the book. But it just felt like they were continually repeating the same mistakes over and over again, and it irked me. 
 I did also feel a little bit weird about the shift in setting; it took me ages to really adapt to the new place, because it didn't quite feel right. It was too different to the setting we've had in the first too. I felt a bit detached. 
 Also, I found the explanation for everything slightly confusing. I didn't feel like it made enough sense, or was logical enough for me to believe. 
 However, saying all of that, I think the last third or so of the novel definitely makes up for the rest. I felt more pulled in by what was going on, and that's when the really tough decisions had to be made. I'm a fan of forcing characters to make difficult decisions, to push them right to their very limits, because I think it reveals so much about them. 
 I started to understand Tris and Tobias a lot more in the last bit of the novel. I understood their motivations and why they did the things that they did, and what they really feel towards each other; this is where I think Tobias' p.o.v.s where most worthwhile. 
 This last part of the novel was where I was becoming as emotionally invested in the characters as I was in the other two novels. As I said, I cried a lot. I've seen a lot of discussion over the ending, which I tried to avoid when it came out, but having read it, no matter how much my eyes sting and my heart feels all achey, I do think Veronica Roth made a very brave decision, and one that fitted everything that had come before. 
 As I said, it took me a while to fully get into the novel, but once I did, I loved it. Roth is a beautiful writer - simple and concise but poetic, too - and I feel that this was a satisfying conclusion to the series. It is hard, I think, to write a book like this, knowing that you can't please everyone, and that so many people care enough about it, that you have a lot of expectation on your shoulders, and I think she handled it really well. 
 I will look forward to anything Veronica Roth writes in the future, and I count this as one of my favourite series. I can't believe it's over. I hate endings.