One thing that no one mentioned....
Buy the BEST machine you can afford. I made the mistake when I bought my first MIG to not go with the 220 machine (I only had 1 plug at the time, and my wife wasnt gonna gonna let me unplug the drier to do some welding!!)
But now that I have proper power supply, I am kicking myself for going with a cheaper, 110 volt machine. Its fine for little projects, but not for the bigger stuff.
I havent learned TIG yet, so I cant really speak to your question.
J