I just got a PowerTig 250 ex last Friday. So far I managed to un-box it, fit a plug to it, power it up, no smoke, and burn a stick each of 6010 and 7018. This week end I intend to try the TIG side of things, some steel and aluminum.
I am strictly a hobby welder, a mechanical engineer by degree, a software engineer by vocation. Early years, stick AC, then stick DC, followed by MIG. I did some tig welding on aluminum a significant number of years ago using a beast of machine, I am thinking a Miller, though it may have been a Hobart. It had high frequency start for steel and continuous HF for Aluminum plus a water cooled torch. Before my wife bought me the Miller Thunderbolt for my birthday, I used a home brew portable engine driven alternator welder for stick and Tig. I got an air cooled Tig torch and made a foot control pedal for the unit and did scratch start steel welding. It actually works pretty good. I even managed to Tig weld copper tubing (a 2 inch diameter chunk). Copper was really pushing my rig as it was only good for around 110 amps. Copper is a tremendous heat sink. No I didn't have to tig weld the copper, mostly I wanted to see if I could. Later I bought a Lincoln SP-130T Mig welder. It is the 220 volt version of the Lincoln portable stuff you see at Home Depot. I think they are up to a SP-180T model as its replacement.
I have built and fixed a lot of stuff with the Mig unit. Lately I have been wanting to do some tig welding on steel and aluminum and I really don't like all the noise and fuss of running my portable engine driven rig so I started looking at Tig welders. I started with the Miller Diversion 185 trying to understand how Tig welding has changed over the years and adjust for the price heartburn. I spent some time on weldingTricksAndTips and liked what Jody said about the 250 ex. Assuming it works as advertised I think it will be more welder than I will ever grow into.