Those are some sweet welds and guns.
I have the HF welder, and for the price it works alright. I learned to weld on a higher quality TIG, and obviously it's much better than a lot of MIGs, but my little welder still makes strong welds. I have welded in 3/8" steel with it, and the weld had some decent penetration.
I like that 10 lb. mod. Good idea. I think I'll do that with mine.