Is the da Vinci code a mediocre book?

I read recently an article abou the da Vinci code (http://pl.shvoong.com/abstract.aspx?id=171501). Is it really a book of poor quality? I think it is a masterpiece. However I haven't read others Dan's book so I can't compare them. Have your read it? What's your opinions?

for me it was good. All Dan's books are goog. My favorite is deception piont.

I think it's a nice book. I managed to read it in just 4 days. But I don't belive that all the things written there are true.

Some of them are only speculations but there is no proof that their are not true. I have book "Templariusze" (i forgot orginal title). There you can read about some facts from Leo's Code. Anyway there is some verity.

I haven't read it so perhaps I am non entitled to answer, but... I've read "Angels & Demons" and, since I live in Italy and speak Italian on mother tongue level and am art historian, I noted errors that Brown could have easily avoided (i.e. while copying some sentence from a plaque in Vatican - just copy it exactly as it is, without ortographic errors! or am I asking too much? there are other examples of his negligence anyway).
It is well written, no doubt, but as to credibility... I decided I am not willing to get angry while reading a book, so I'll just skip "The Da Vinci Code".
Maybe some time, when I've got over "Angels and Demons", we'll see...