I read the Da Vinci Code when it came out, and just didn't find the narrative to hold together. The logic was bad, there were gaping plot holes, unbelievable story lines, etc. It has been too many years to recall the details, but I do recall my overall impression being that he just wasn't a very intelligent author, and I couldn't muster up enough suspension of disbelief to enjoy it.

That being said, I do know intelligent people who enjoy his work, and his books and movies have been successes, so I don't take my own bad impressions of his work too seriously - I'm clearly in the minority. So if other people enjoy his work, I'm not going to come down on him or them because of it all. To each their own.