What OSs does the MJ software run on?
The big 2.
I've plugged mine in on MacOS (10.7 and earlier), Windows XP, Vista, and 7 and it works fine.
When you plug in the unit you just run the little software, it checks for any updates and runs them if needed, then you're ready to call.
Takes all of about 45 seconds from when I plug it in, till I start dialing home.