I'm a very happy user of SizeUp[0]. I did pay $13 or so, but money well spent. Functionally, I wonder if amethyst is the same or better. It's definitely nice to have this free option.<p>[0]: <a href="http://www.irradiatedsoftware.com/sizeup/" rel="nofollow">http://www.irradiatedsoftware.com/sizeup/</a>
Let me put in a word for ShiftIt.<p><a href="https://github.com/fikovnik/ShiftIt" rel="nofollow">https://github.com/fikovnik/ShiftIt</a>