How about calling it "Mountain Lion" or whatever cat they're at in the system info but having the full name be "Mac OS" and dropping the "X"? So iOS and Mac OS.
The "X" was supposed to mean "10" (after OS 9), but they just stayed there because "XI" is lame. I'd call Cheetah and Mountain Lion different enough OSs for them to not both be OS 10. Windows at least only puts numbers on their OSs if they make sense (although they've come up with idiotic names like XP, Vista, and ME). Sadly, XP is still their best.
The "X" was supposed to mean "10" (after OS 9), but they just stayed there because "XI" is lame. I'd call Cheetah and Mountain Lion different enough OSs for them to not both be OS 10. Windows at least only puts numbers on their OSs if they make sense (although they've come up with idiotic names like XP, Vista, and ME). Sadly, XP is still their best.