Depends, if you're studying something that rarely changes I'm sure books are great, but I've been through three Java books in the space of four years as each time a new version comes out the old book isn't as useful. Plus if a book is printed with a mistake you've got no way to correct it other than pointing people to a web site or something...

The web does have a fair few tonnes of crap, but I wouldn't say that books have an advantage, get the wrong book/author/publisher and it might be based on opinion more than fact as well and yet because it's a book, people may take it as fact...

Yes for a fast changing subject like computing then a PDF will probably be better. It can be changed very quickly. Though for older subjects like history or geography then a book will be better, though supplemented by online research. Though for many exams even university exams they could actually get people to log in for the exam. Any research that they do could be done online from the same computer and even if they cut and pasted as long as they provide references then that should be fine. It would be similar to a working situation.

Indeed, I see a diploma that you have to buy a validation code for, which will require upgrading every few years...