Vulcan welder

One should ALWAYS be concerned about duty cycle... because when you aren't, that's when you'll overheat the machine, either it's internal components, or the hardware (torch, gun, electrode holder, etc.).  Duty cycle is the 'true' rating element of a welder, the litmus test of it's functional strength.  If you're tacking together light steel at 90A on a machine that's advertised as 120A at 60% Duty Cycle, you'll find yourself waiting more than working... because that duty cycle curve will STILL have you well below 100.  IF it's aluminum you want to weld, you'll need considerably more power on tap, and when you're in the middle of a beautiful bead and the torch starts to overheat, you have to bail and wait.

The challenge of multiprocess machines, is that there's some that do a good job at switching between process types, but most don't.  If you have very little shop space, and very little welding to do, a multiprocess will do the job, you'll just need to reconfigure it each time you change modes.  Going to stick welding from any mode is no big deal, so long as you're not carrying it around, leaving the spoolgun or feeder and gun attached, or the TIG torch, cooler, etc., all set up... but making it portable means you've got lots of fussing to do... and that's why most shop TIGs are relatively stationary.

If you're not needing portable, there's lots of other ways to get a good result... and they all point to getting a serious surplus industrial machine.  I have two TIG machines... one is a Miller 330AB/P, the other a Lincoln IdealArc TIG 300, they're both big and beastly, but have serious ratings.  Frequently, these machines turn up on auctions and company sales, and while they DO age and wear, they clean up and recondition easily... and I got both of mine for less than $400 each... including all the accessories (torch, hoses, cooler, foot pedal, etc). which frequently cost as much as a whole new 'big-box' machine.

The GOOD part about old-school TIG machines, is that IF they do AC AND DC, then they're generally always single-phase, as it uses the line frequency to provide AC.

That said... read the fine print- if the welder is DC output only, then you won't be welding aluminum... you need AC imbalance to help clean the weld.

I've not used one myself but know of two parties that have purchased the brand. No problems I've heard of but neither are any kind of production shops, only self repair type(s) like many of us.

I know two other parties including some in family that have purchased the "Titanium" brand they offer and have had very good service from them. However both of those are too small for what's asked of them and are kicking out of duty cycle which is not a fault of the machine.

FWIW.