Did you have a mac partition open and mounted on the Amiga side when it happened? I'm convinced that's the trojan that causes the Hard drive to rip itself to shreds.
I'm very careful now, when I transfer stuff from the mac side to the amiga (or vise versa) I always shut down the mounted mac partition on the Amiga side)
So far I have had fusion running for over 4 months now with no problems, then again I have it on a second hard drive too, so I'm not too worried.
Is it worth all that effort? You kidding? yes! there are some great goodies available on the Mac side!
Mikey C