Why Run Linux On Macs?

jones_supa writes Apple has always had attractive and stylish hardware, but there are always some customers opting to run Linux instead of OS X on their Macs. But why? One might think that a polished commercial desktop offering designed for that specific lineup of computers might have less rough edges than a free open source one. Actually there's plenty of motivations to choose otherwise. A redditor asked about this trend and got some very interesting answers. What are your reasons?