I have used that torch mainly on thin gauge mild steel, very thin, down to 22 ga. I have used up to 1/8" mild steel and it's as effective and pretty as TIG.
The cutting torch attachment works good, but on thin gauge stuff an angle grinder is just as fast (since you have to change the tip and adjust the pressure a bit). I have played with it on aluminum too, but I have a really good TIG machine that I use for all of my aluminum stuff. The torch is high quality and IMO, leaves you with weld that is softer to clean up and doesn't put near as much heat on the panel that you are welding. The other thing is that it is very comfortable, no welding hood, just a pair of gas welding glasses (from DHC) and some thin work gloves. And at 4 PSI, you use hardly any gas, compared to Stargon/Argon for MIG stitch welding. So, I'm a fan.