I loved Da Vinci Code and other earlier works, but this one drove me crazy. It gets bogged down when he describes the city of Florence in such painstaking detail that you actually forget what had been happening before he explained the history of Boboli Gardens! I use that example because it is as far as I got. Whenever Langdon is present it slows down for this exposition. Other parts without him move at a much more reasonable pace for an "action" novel. Too bad, because I was really looking forward to it. Fortunately it was a library book and not a purchase!
This is one of my favorites of 2013. It would make a great book club selection, as it brings up interesting questions when you finish. It is sort of like time travel with a twist. The main character relives her life over and over again, each time changing things based on subconscious memories. She is born in 1910 and after countless lives she understands the evil of WW2 before it happens and tries to stop it (which you see in the prologue).
It's a great book that I highly recommend!