Just finished this book about a half hour ago. Book of the year for me so far. I loved it. I'm a huge fan of The Stand and i thought this was just as good. More original ideas about an end of the world scenario and you come to know the characters a lot more.
The whole idea of The Colony was great. I loved the imagery of the buses and trains taking the children to safety after the first outbreaks. The idea of the wall, the Watch and the lights was really cool. I also loved how the virals felt compelled to come home so their loved ones stood the mercy for seven nights. Very cool imagery and cool new ideas in this book. I also loved the idea of the twelve and how the virals they made were mentally attached to them. The reveal about Alicia and what she becomes is also really cool.
I'm really looking forward to the next book in this series. Highly recommended!