I've not yet see MOS or AmigaOS 4 running...
I've see them only in a demo movie.
But I can say something about BeOS (PC). It was great!
In few month I learned to program it's API and I wrote a game:
ThemeTris (you can find it on bebits.com).
It was "simple" and powerfull, not another Windows like OS.
I think AmigaOS 4 will be great!
