It was greatly hyped, which should be a warning, but then the Harry Potter books were also hyped, and (I've not read them, so this may be rubbish) they were not pap.
When I decided to read DVC, I went and bought it, and they were doing a "3 for two", and there were all his other books, so I bought 3 of them, and my son had borrowed the 4th from a friend, so I ended up reading all of them.
It was only because I'd bought the bl.oo.dy things that I persevered. The actual plots were OK (Digital Fortress was laughable, but then I know more about that sort of thing than TAMITS), and let's face it - these are works of fiction - they don't have to be soundly based on fact and history.
But as I said - the writing, plot development, characterisation etc, are execrable. He is getting better - DVC was almost passable, but I don't plan to read any future novels of his.