I have that exact welder and it performs flawlessly. I have stitched on plenty of subframes and built all sort of things with it and it is like a Timex. I haven't even paid attention to duty cycle and it just keeps on laying it in there.
I bought mine at Northern Tool also.
Just make certain you use the proper size wire no matter if its flux core or you use 75/25 shield gas. The Flux Core puts a lot more heat into the metal so be aware.

GL