Personally, I thought it was appalling... Any attempts at creating suspense were rendered hilarious by the ridiculousness of the things being suspended. (I must change ze batteries! There's NO TIME!!!)
Anyone interested in going to see the shots of the various churches etc. in the Vatican and Rome will be disappointed. The action moves too quickly and there's simply no time to take anything in.
Several characters (notably one of the antagonists, and the head of the Swiss guard) are simply not developed at all, and characters that might appear significant at the beginning are quickly left behind.
It's obvious whodunnit almost from the beginning. (And I hadn't read the book)