>>1
Why don't you try them yourself and find the one you like?
It doesn't really matter too much to me which one I use, as long as customization is easy. A tiling window manager is almost always as minimal as possible when you install it, so as long as the core features have most of what you want (and the rest can be enabled through customization), it doesn't really matter.
That being said, I use XMonad (along with a Gnome status bar). I used to use StumpWM (because Common Lisp is a lot more fun for customizing things than Haskell), but I got sick of manual tiling.