Yes you have to use the shell now and then, but it's so effective, it's almost spooky.
All those UI promises of bloated window managers, swiped away with an absolute minimum window style. Maximum space, maximum speed, minimum distraction.
I'm going to talk about it today in the "Ryo's Wochensicht" netcast. Unfortunately it's going to be in German language *bummer* :)
But to get a good view, you can watch the video below from gotbletu. It seems to be a slightly older version. So the keys have changed here and there. But all in all you see how fast and awesome this wm is.
You can get more info and download everything you'll need from i3wm.org.