This series is definitely worth a read, although, I have to say, I didn't like this book quite as well as the first one.
At the end of Divergent , Tris -- our main character -- had successfully transitioned from the family's faction of Abnegation to her new home with the Divergent. And a horrible war had just broken out.
Insurgent continues the story, as the now homeless Divergent population finds temporary refuge with Amity, and then with Candor, giving us a look at both of those factions, too. It's becoming more and more evident that none of the factions is entirely without merit, or blame. (Well, except for the Erudite, but I'm sure we'll get to them in the next book.)
I particularly admire the way the author handles the romance in this series. It seems relatively authentic for a young girl like Tris, and yet it's neither cloying nor exploitative. I'm eager to see what the next book will be like, but I guess I'll have to wait until it gets published. Sigh.