I am using it quite often for the OS4 port of unrar because all MOS, WarpOS and 68k ports of unrar I tried did suck, causing system freezes or were only able to unpack one archive and then did not work anymore until I rebooted. After rebooting they worked again, but just for one single archive, so I had to reboot again... but the OS4 port works quite perfect.

Some time ago I used to use Mencoder OS4 port with os4emu until Fab released a more recent MOS port.