I have always been a fan of fringe operating systems.
Between 1989 and 1992, I learned and used VMS, OS/2 2.0, NeXTStep on those beautiful cubes, GeoWorks, AmigaOS, and probably half-a-dozen others that I don't recall at the moment. I loved the diversity, the differences, the similarities. Booting an unfamiliar operating system for the first time always gave me a rush of geeky machismo, usually accompanied by the irresistible urge to grow a thick mustache and learn to fence with a saber.
Perhaps it's a sickness peculiar to geeks. Or maybe it's just me.