Why EMC?

Other than being free, what is it that draws so many folks on this list to
use EMC? I would have thought that, with so many G-Code interpreters being
available for DOS and even for Windows, that the necessity to change
operating systems (and to learn a new OS) and then learn to "tune" and use
EMC would be more effort than many would want to expend with so many
alternatives.

Please don't take this question as either a flame or insinuation that EMC
and Linux are somehow "bad". I'm just interested in understanding why this
particular G-Code interpreter is so appealing.

-- Jerry