I've been doing no-risk repartitioning (without losing data) without problems with some other software on the Mac, especially when I was making the Mac Linux-ready; I forgot the name, but I think it's been discussed here on MacRumors before.
I'm sure this new FWB tool is to be a *LOT* more user-friendly, and that's a good thing.
good deal, i have partition magic on my pc right now..but i had some troubles with it before (didnt restart into windows but instead put in the linux cd and booted from there..lost everything cuz of that....)