There are a surprising number of Preview defenders here. You guys must have never had to open a 500+ page document, because for me, that's an all-but guaranteed way to make Preview crash. Preview is only best because the major alternatives (Acrobat) suck more.

PDF readers I actually like: Zathura (obviously), sioyek (if you like customizability and Vim-like bindings, this is a good one!), and Skim.

Everything else tries to do too much (read: be an Acrobat substitute).