Daij In my opinion I think you should read all three books because I've read all three an I think Insurgent was better than Divergent and Allegiant because in Insurgent in a way I was kept guessing about what would happen next. However once you finish reading Insurgent your start to predict what's going to happen in Allegiant and once you finish reading Allegiant you're going to be sad but then you'll think back as " Oh... I should of known that was going to happen."
Bbgirl28 I honestly only liked Divergent. However, I did find that Allegiant was better than Insurgent. I think you should read Allegiant so you know exactly what happens and how the trilogy ends. Even if, in your opinion, it ends terribly, you can at least say you read the entire trilogy. Good luck