While acknowledging that we can’t judge books by their covers, how much does the design of a book affect your reading enjoyment? Hardcover vs. softcover? Trade paperback vs. mass market paperback? Font? Illustrations? Etc.?
If a cover catches my eye I will pick up the book and read the back blurb to see if it is something I want to continue reading and then I will buy it or check it out at the library. Sometimes I will study the cover of a book to see if it will give me answers to questions that come up as I read the book, esp. murder mysteries.
I will buy soft covers because they are cheaper. There have been times I buy hardcovers because I like the book so much I want to keep the book, like the Harry Potter books, the Little house books, and any books buy Anne McCaffery.
I prefer mass market books again because they are cheaper. But some of my favorite authors are in trade paperback books like Philippa Gregory and Jean Plaidy. So I have no choice if I can't find them in the library I have to buy them.
I don't like font that is too small It does make it difficult read.
Sometimes illustrations will distract from a story and sometimes they enhance a story.