The book is better than the movie.
I'll be the first to admit that this book doesn't live up to the hype, but to be fair, the hype was huge. This isn't anything that sensational, but it's still a good read. Just like with Angels and Demons, it's a fast-paced, suspenseful thriller (though not quite as tight as Angels and Demons) with some thought-provoking issues (though not as well-balanced, and considerably more pretentious and preachy than Angels and Demons.) There's really no reason for anyone to be offended by this book, and I don't personally find any of the ideas all that sensational. If you want a Dan Brown thriller . . . I'd still recommend Angels and Demons. But this one's pretty good, too.
I know that this book was a huge hit and a blockbuster movie, and I know that writers sometimes have to take liberties when writing historical novels, but this book was awful. Let me explain. I have a degree in Art History and much of the background for this book is rooted in art and church history. Brown takes one excessive liberty after another to make his book work, to the point where it is insulting. It is especially insulting to Christians, but even those with a passing knowledge of art history will find plenty to complain about. Is it an exciting story as it moves from venue to venue and from action to action? Certainly, but I think those who write historical fiction bear some responsibility to stay true to the facts as we know them as much as is possible, rather than completely reinventing it to sell more books.