I've had the Chinese TIG/Plasma/Stick welder unit now for about a year and am happy to say it is well worth the money. I got it on Ebay, the home of all things Chinese, and immediately found there is no documentation and damn near no support for it!
Mystery number one was: where does the gas go in and where does the air go? Answer: in the same (one) port!
So, I documented how to set it up, based on my own experience and info I scrounged around the web. I might add to that to check all electrical and gas tight fittings and connections, a couple were loose or leaking on mine.
Also, if you've never used TIG or plasma before, keep an eye on the little bronze pieces inside the guns, where the arc occurs. They are consumable and, even though they make look fine to you, after a while they will begin to burn out and dramatically impact the quality of welding or cut.
Don't use welding magnets, it screws up the plasma arc.
Finally, respect the duty cycle. Weld or cut for a half minute, let it cool and rest for a half.
Like most Chinese made tool or machines, I had to tweak it and was unimnpressed with their "quality lack-of-control" as far as pre-ship testing and of course, the complete lack of user documentation. But, other than that, the machine itself seems to be made of pretty good stuff. I use it regularly.