Here's a gripe I have with pdfs. I don't mind they can't be edited, that's fine and while i like to be able to copy and paste turning that feature off is okay but when I can't print the pdf because printing is disabled I'm not going to buy the product.
If it's a pdf preview of a print only title, that makes some sense but it had best be free or almost free if that is the case. If it's a pdf only title it's never going to be purchased by me if the print option is turned off. I like to use my gaming materials at the game table and don't fiddle with electronics there. I also love the ability to scribble the heck all over a printed pdf, I've actually bought pdfs of print books I have so I can in fact scribble all over them as I play and not ruin the nice bound original copy. But no printing , no scribbling, no printing no use at the table top and if I'm not going to be able to use it at the table top I'm not going to buy it.