Wish there was a cool reason to tell you, but it was just because somebody happened to be extolling the virtues of i3 in a similar HN discussion a few months back, so I gave it a whirl. I'm sure Awesome and Xmonad are great too, but all my needs are met so haven't really had a reason to shop around.

Looking back on all the hours I used to spend tweaking and fiddling with configs for things that I no longer use has made me sort of a setup minimalist -- anything that's not broken for me usually stays pretty close to stock these days.