Flip a coin?
If you are doing light hobby type stuff, maybe a couple of hours on the weekends, the MOSFET should be fine. However, if you are gonna push the duty cycle, welding all day, for hours and hours, I would go with IGBT, they are simply more rugged. Same thing goes for multi process over single function machines, the multi seem to be suited to more light duty usage . Also there is the time involved in swapping the machine over and remembering to switch everything to the proper settings for each process. Nothing like forgetting to switch from air to argon when you Iight up your TIG torch. For small projects it may not be a big deal, but depending on what you are doing it can get old in a hurry. Budget and space can be a deciding factor. If you only have room for one machine a multi makes perfect sense.
Last edited by Rambozo; 11-13-2013 at 03:26 AM.
Long arc, short arc, heliarc and in-the-dark!