It's a no brainer, not worth the hype and definitely should not be taken as factual!
But for all the bashing, if people just read it as a rather weak people-pleasing kinda... thriller thing it's okay. Just not great, or even good.
It's something to read when you don't want to think, if you're in hospital or just in need of something to read during a short space of time. Something that goes in through your eyes and out the back of your head.
It does not challenge the bible. It is not fact. It is not a well written book, but it has plot and storyline. Brown isn't the best writer, but I've seen much, much worse. I'd say he was readable.
I see Mosse (Labrinth) as a horrendous writer and I could not get page 2. Dan Brown, and this is a matter of opinion at least did not irritate me by describing a drop of blood to be like a firework. His writing style is simplistic and un-challenging. Hardly a crime.
He may claim it's well researched, I don't know, I rarely read author interviews unless they're an author I like. I don't care. To me, it's a bit of fantasy that can seem like fact, which I suppose makes it entertaining. Who knows.
It's not really worth my time and I wouldn't want anyone else to waste time reading it, but whatever floats your boat...