In my flight to Peru I read this book from Dan Brown. Although I was already disappointed by "The Da Vinci Code". I decided to give "Angels and Demons" a try. Let me go into my analysis.
It is very easy to read. Do not expect great literature, remember Dan Brown is not Gabriel Garcia Marquez. The actions described in the book are interesting, but too fantastic (more than in the Da Vinci Code)to be taken seriously. The end of the book is very bad. I will not tell you what happened, just that is an overused type of ending.
With respect to the scientific background, it is well known that antimatter is made all the time in particle accelerators. Particle collisions are done all the time. The idea for storing antimatter is interesting, but if it were as simple as it is mentioned it would already have been done. I know it is just a novel, but some people might really believe it and that is a real problem.
There are some important historical facts that are correct, specially the ones regarding the history of the Catholic Church and the relation of the Sun´s worship and Christmas. Morover, I learned about the Illuminati. The book gives the wrong message when it suggests that science and religion can accept each other when they are the exact opposite. The scientific method does not have space for faith and religion is all about faith. A scientist can have faith in a god, and, so as it does not interfere with his or her work, it is ok.
As a summary, I do not recommend it, but you should judge for your own self.