Definitely go with a 230V machine, Miller 180, Hobart 180 (made by Miller), Lincoln 180 are only good for a max of 5/16" steel and 1/4" AL.(spoolgun attachment) in one pass and that's with a duty cycle of 135A @30%. The Miller Passport & Millermatic 211 are good for a max of 3/8" steel & 1/4" AL. and are dual voltage. Anything thicker (1/2" one pass) and you need to step up to the Miller 252, I have the Miller 251 which the 252 replaced awesome machine. If your looking to go with a Tig machine it again depends on what thickness you plan to weld and if you want to weld AL. If you just want to weld steel, stainless and some of their alloys you only need DC, for AL and other alloys you'll want AC/DC. The new Miller Diversion 165A is good for 3/16" Steel or AL (one pass) ,a Miller Dynasty 200A machine is good for a max of 1/4" steel or AL (one pass). I have a Miller Dynasty 300DX AC/DC with the water cooled torch which is good for a max of 3/8" steel or AL. (one pass). Stick with a a good brand, Miller, Hobart, Lincoln etc. they all have a good track record and with Tig welders the consumables are a lot easier to come by.