The Da Vinci Code was a ridiculous hype, enough so to make anyone get fed up with it. Then the hype spread to a lesser extent to his other books, and now to the new sequel. It's a lot like the visceral hatred of Twilight - Dan Brown and Stephenie Meyer aren't necessarily worse writers than many others, but they are hugely hyped and everybody talks about them, leading to frustration among those with better taste. Harry Potter escaped that reaction to some extent, as did that other recent enormous hype (at least here in Europe), The Shadow of the Wind. I'd say largely because Rowling and Zafon are rather better writers.

Personally, I found Dan Brown's books entertaining - and Meyer's, for that matter - even if his constant cliffhangers get old very fast. Still, reading the books is no worse than watching your average James Bond movie or rom-com.