After receiving a softcover version of Theorems & Thaumaturgy, and a copy of Realms of Crawling Chaos (which is, by the way, excellent), I am in love with this format! I've always been a staunch defender of hardbacks in the past, but I now realise this is purely down to my distrust of so-called "perfect" binding (where all the pages are glued to the spine... just waiting to unglue themselves in a gradual, disappointing decay).
The staple-bound books remind me of the old B/X and BECMI books from the 80s, which is great!
Now I can't stop daydreaming about a 2-book edition of Labyrinth Lord in this format -- one players' book, with all the classes, spells and the basic rules, and one DM's book, with the monsters, magic items and more advanced rules. How awesome would that be?