I recall using GEM on the Atari ST (the first computer I bought, for about $50 at a garage sale), and then using Owen's FreeGEM distribution at some point later on. I didn't really think it fit in with the theme of being DOS-Windows-OS/2 ish, although the Atari ST veresion seemed to use some modified form of FAT on floppy disks (based on the fact that the filesystem was readable but with mutations on the family DOS/WFW 3.11 machine). I certainly didn't feel like Windows in the same way that OS/2 feels like Windows.
