First, if you refer to this thread, it will be clear that you are talking about two different classes of machines.
http://www.aws.org/cgi-bin/mwf/topic_show.pl?dln=25148;pid=80284#pid80284Second, as JohnnyUtah says above. you need to state your intended use.
FWIW, I bought the PowerMax 30 and a cheap compressor (Briggs and Stratton 10gal. oil lube. 4.5 cfm at 125psi) and have been using it for about a year now, on sheet metal to 3/8" plate. Highly portable, excellent cutting, and very easy on consumables. (I added a filter/dryer). The Hobart Airforce 400 (comparable model) would be too heavy to hang on the compressor, as I did with the PM 30, to make it very portable.