In short: Possession by Elana Johnson has an interesting concept and a likeable heroine, but ultimately, the novel's downfall is its extremely fast pacing. 
 If there is one thing I noticed about Possession by Elana Johnson, it's the novel's extremely fast pace, which can be seen as both a blessing and a curse. Sure, it means non stop action and never a dull moment, but at the same time, things moved too fast for me to truly absorb the events that occurred in the novel and to get a feel for most of the characters. It also means that how the dystopian world in Possession originated was summarized in one paragraph, which is not nearly enough to suffice my curiosity. 
 The relationships between main character Vi and her two love interests in the love triangle fell flat for me, also because of the fast pacing in the novel. With Zenn, we get to see so little of him that I never got invested in his character. With bad boy Jag, things progress so unnaturally quickly that it seemed unrealistic and silly. I mean, they declared their love for each other only a few days after they met! 
 The world building was okay for a dystopian (world building is the number one must that I expect to be done well in dystopians). There were some interesting concepts but again, they were not given time to fully develop due to the fast pace of the novel. One thing that I thought Johnson did do very well was all the terminology that the reader has to understand to grasp the concept of the world: this could have easily been confusing with the fast pacing, but I thought Johnson handled it well and I found I could follow it fairly easily. 
 My favourite part of Possession would have to be the heroine, Vi, who was instantly likeable. A thief and a liar, Vi speaks and thinks in a very typical "teenage" way, with a very sarcastic tone that was enjoyable to read. Unlike some of the other characters, the reader will instantly get a feel for her personality and her rebellious nature as a "Free Thinker". 
 Overall, for me, the fast pace was really Possession's downfall. That said, just because this novel wasn't for me, doesn't mean I don't think someone else couldn't (and hasn't, from reviews I've read) enjoyed it a lot more. If you are someone who gets annoyed by very slow pacing in books, then I would recommend Possession to you; you would probably enjoy it more than I did!