I read it in two days, and it probably wouldn't have lasted that long had I not been working. 
 I was really drawn into the world from the beginning - I really like dystopias as a rule, especially those involving humans being sorted into groups, and here the concept was really mastered by the author. Actually, I was more attracted to the story of Tris (view spoiler)[being an Abnegation and becoming Dauntless (hide spoiler)] than to the whole Divergent things, but both function well together. 
 The only thing that (slightly) disappointed me was the end, or rather the last 20% of the book, which feel a bit rushed, especially at the start. Yet I still enjoyed the challenges faced there and the growing dark tones the book takes. 
 I'll definitely rea the rest in any case, and I'm hoping the movie adaptation will do this book justice, although the trailer really seems to show a whole different take on the story, which is quite infuriating. Let's hope it's just the trailer.