Back when a nuke I was on used Chemtron Atom Arc, it welded ok but the starts were really fussy and if you didn't get the arc length just right there would be little porosity in it. It took some discipline and getting used to, it looked like it cost them millions to me. Its been a while but as I recall you had to really long arc it for a split second, made for little splatter etc but the pits were a problem, some of them even looked good till you go to clean up or hit with grinder, real fine and on general fab maybe not so much of an issue but where space, location etc was a problem it could be a challenge.