All other things being equal–do you prefer used books? Or new books? (The physical speciman, that is, not the title.) Does your preference differentiate between a standard kind of used book, and a pristine, leather-bound copy?
As long as it is in readable shape, not falling apart, I really don’t care if a book is used or new. I am hard on books myself so used is okay with me. Now, when it comes to authors or series that are my favorite I will buy the book new. I will always wait until the end of a series and buy all of the same covers. I hate when they change them part way through.