vmware runs a virtualised environment complete with seperate copy of windows, because of this you can use a *** if you want to have a different IP per D3 bot
isboxer runs on top of 1 windows install and just uses software tricks to seperate the d3 instances
vmware has more overhead and performs slower but provides a more true separation
Probably has to do with the whole injuction thing. Bossland and his crew were probably prohibited from assisting in letting germans bot and decided that saying V P N should be blocked.