Is a microwave oven transformer welder any good? (plus a softstart circuit)

Four years ago I built an arc welder out of two microwave oven transformers (https://www.youtube.com/watch?v=_EA-nzDJbKo). Back then I had absolutely no experience with welding. Now I have had the machine for four years and I am ready to give a strong thumbs up for the concept of building a welder out of MOTs. I have upgraded the cooling (burned a winding once) and added a softstart circuit (NTC resistor based). No more blown circuit breakers!