No, I have not used it, but I believe that it would work well enough. I have used a Miller Diversion 165, which worked well enough for a $1600 unit, but was wildly over-simplified for my taste. I understand your skepticism about anything not Miller or Lincoln, but check out
this review of the PowerPro 256 and another video series going over T
IG welder settings with the same welder.
Jody, the guy who runs this site, is brutally honest and very knowledgeable. You can see that the welder works just fine on aluminum. It appears that all of the inverter controls let you get a very nice arc. Perhaps Miller or Lincoln would last longer, but for an FRC team you don't need the 100% reliability for the next 30 years that you'd get with Miller or Lincoln.