Actually, the novel AaD is better than the novel The DaVinci Code...but "better" here means "less preposterous, less unbelievably silly, less full of eyerubbingly inaccurate howlers, containing less amazingly bad writing and less misshapen as a novel".
AaD is at least great trash (in parts) and very entertaining (in parts). The DaVinci Code is pretty much just potboiler trash with one heck of an anticlimax. And don't get me started on the descriptions of art, architecture, religion, linguistics and history in that...speaking as someone who once considered majoring in Art History, that Dan Brown claims he studied art in college and that his information is accurate and taken from that is just hilarious. The sad thing is, a "layman" would actually believe him and swallow it all whole.
As for the movies, The DaVinci Code is actually a terrific thriller. It's a solid 3 star movie but no one seems to have liked it but me.
Same for Angels and Demons- mild thumbs up.
Edit: Tom Hanks is, however, miscast as the hero. Maybe it's that he's too old but he never seems right. And what's with that hair? He never has that hair in any of his movies.