I thought it was pretty good and was mostly faithful to the book. I can see how if you didnt read it though some parts might have been confusing. There were a few things they could have explained more clearly. Couple things:
- dont think Tom Hanks was right for the part
- french girl was hot
- flashbacks were a little overdone
Someone mentioned that many reviews slagged it:
http://www.rottentomatoes.com/m/da_vinci_code/
However the collective reviewers monitored by RottenTomotoes have little credibility for the most part as evidenced by:
http://www.rottentomatoes.com/m/signs/