My wife and I have read both of Brown's books made to film. The DeVince Code dragged and lacked the character details that made the book "non-stop" reading. Same goes for the Angels and Demons movie.
I suggest that you read the book before you see the film. It will help fill in the missing pieces. Loved the action and Tom Hanks. Never got connected with the female lead, what's her name.
The ending is a nice twist. The tension of electing a new Pope was intriguing.