Save up a little more and buy a quality welder. If it is for panel repairs any amperage will do, but you want one with good adjustment so you don't blow holes in things.
you can get ones that pulse and that too which are useful, but not essential.
140amps can still do 6mm steel welds in a single pass, if you're wanting to tig as well buy a second machine for tig as those 3:1 machines are generally not good at any function