I agree with these two gentlemen. I recently went to Tig, a fairly light duty, AC/DC buzzbox conversion. I've used stick for more than 30 years, OA for about 10, mig for a couple years.
I enjoy the flexibility of Tig, but anyone considering the buzz box conversion should seek out a high-freq unit, I don't think Tig is much good without that, you'll just be eating up tungsten and contaminating your weld puddle continuously. At least that was my experience.
I guess they all have their place for particular uses, but right now I would not trade the Tig for any of the other units. Someday I may need to step up to a >$1000 Tig unit, but for now I'm delighted with the results I'm getting.
Dan