If all you're doing is sheet metal, the Eastwood welders are a good bang for the buck. I have a Miller 252 which is a very nice 220v welder and will weld just about anything BUT I do a lot of thicker welding and didn't want to have to switch wire, rollers and liner every time I do sheet metal. I bought an Eastwood 135 110v machine and it works beautifully. I use a mixed gas and .023 wire and follow the suggested settings on the welder.

In this day and age, unless you're building bridges or fixing tractors in the middle of a corn field, I don't know why you'd want an arc welder. If you want to do thicker metals, buy a bigger mig. These days a quality 220v mig will have the capability to weld everything from tin foil to 1/2" with a change of wire rollers and whip liner. Those accessories are fairly inexpensive.