The question of the day is: Hardcover, Softcover, or Digital?
If I’m going to play the game at a table, I prefer a softcover “trade” sized book (typically 6×9), like the Dungeon World book. That’s the easiest format for me to flip through and reference on the spot.
If I’m reading and keeping the book because I love the designer, the system, or something about it in particular, I’d like hardcover. This is how I ended up with the Chuubo’s tome on my bookshelf, right next to the Burning Wheel tome. I haven’t played either game and when I do play Chuubo’s, I’m more likely to leave this on the shelf and bring the ebook to the table.
No matter what, I desperately prefer to have an ebook/PDF version of the book in addition to the print version. I travel to cons and am not interested in carrying a 30-lb book with me. I look stuff up when I’m at my desk and don’t want to trek downstairs to find the book. For all I know, I’ll move back into an RV and go vagabonding again, in which case I’d definitely need ebooks if I want to keep gaming.
I also very much prefer game books that are under 200 pages. Funny thing. If you don’t have a zillion rules for how to commit violence against each other, you can get away with a lot fewer pages.