Otto - I bought the 120 volt unit because I wanted portability and I'm only doing light gauge work. You'll find all the specs for these machines here:
http://www.usaweld.com/product_page/...er/tig120.html
I just got mine recently and it does a GREAT job. It was $599 but they have a unit that's even smaller for about $250. Unfortunately...it's not on their web site. You have to request their catalog.