If I may be a voice of disagreement here. Having welded with STT/RMD technologies (I forget what Fronius' version is called), since its inception it is my belief that welding roll outs on low alloys, and probably even higher alloys like stainless steel is a waste of time and money. This was not what it was designed for and this is not where it really shines, though Linclon aggressively marketed it as such.
Where it does shine is in position work on higher alloys and it also makes easier a spatter free interior for pipe, though a well adjusted CV machine can weld spatter free SC roots.
The arc is essentially cut off at a certain point allowing fast freeze capability, while the plasma boost is the thing that saves it as opposed to the fusion problems associated with standard spray pulse type applications, though industry info notwithstanding my experience has been that fusion problems are greater than with standard CV, because it is after all a form of pulsing. A pulsing imposed within a short circuit, but a pulsing nonetheless. In side by side comparisons of standard CV and wave from machines root passes are much more readily identifiable as having achieved fusion and penetration than the pulsing SC machines, and at much less the cost.
In comparisons with GTAW the big advantage to GTAW is if you can trust your tacker and he gives you full pen tacks you can consume right through your tacks with GTAW and never stop on roll out welds. It doesn't matter what you do with GMAW you have to stop. We did this very thing for years in a fab shop I worked in and maintained less than 1% reject rates. If a tacker misses an edge or has lack of fusion you can catch it. If there is porosity it will let you know as soon as the gas expands. And you can't even see where the tacks were. The one disadvantage is your tacks have to be GTAW of course.
When it gets right down to it the controlled wave form SC machines have a distinctive advantage but in limited applications.