Ebooks. Kindle has a nice display showing how much is left in the chapter. It has a warm light back light, and i can take multiple books with me on a trip (i have some unfinished books).

I can put down the kindle without losing the page, or having to bookmark it. And i can sideload the books for free.

Physical books are tempting too as i can get them free at a library and very cheap second hand, but i know i would still prefer to read it on kindle where i can choose the font size I like.