Extremely user unfriendly though. Just installed it and it doesn't even sensible defaults for you to hit the ground running. Their answer: "Read the docs and write your own configs." Nobody has time for that!
Edit: Another commenter suggests http://spectacleapp.com/ - works really well out of the box - in fact it does what I expected Slate to do.
Edit: Another commenter suggests http://spectacleapp.com/ - works really well out of the box - in fact it does what I expected Slate to do.