I almost exclusively read books on paper. Sometimes I'll take my kindle when I travel and don't want the weight of a bunch of books, but otherwise I stick to paper. Reading on electronics messes with your sleep. I also like books that can't be changed or that I can make notes in or highlight (since I mostly read nonfiction)

I mostly read nonfiction because when I read fiction (a story), I like to sit down and read it cover to cover in one sitting even if it is a 500-1000 page book. I have too many responsibilities to do that now, so I stick to nonfiction that is easier to read a small portion at a time.