Quote from: cp1 on January 05, 2014, 05:11:32 AM

I prefer installing ubuntu onto the USB drive instead of creating a persistent live image -- I think it's just cleaner. But, both will work.

The key benefit of LiveUSB over full install: the resulting LiveUSB Armory will boot on the full variety of PC hardware supported by the OS.
With LiveUSB, the owner has a much better chance of being able to successfully use their offline Armory when the transaction needs to be done on an alternative computer.
The mods in this process are meant to overcome the tradeoffs of LiveUSB vs. full install.