Could you elaborate on why you would go TIG first if you had a do over?
I'd guess because with 'enough' machine, TIG can weld
anything.
An AC/DC GTAW machine can weld steel, aluminum, stainless, copper, and pretty much anything else that is arc weldable. All using just a tank of argon. (maybe you might want/need an argon-helium mix for some 'thick' aluminum.)
But TIG is a 'slow' manual welding process.
As to the OP, generally get the 'biggest' machine you can afford ($$ and power wise).
You can usually turn a big machine down somewhat, but you can't turn a 'little' machine up any higher on power than its 'max'.
The 120V (or 110V

) MIG machines are (usually) nice machines. When used within their 'limits'.
But those 'limits' are rather easily outgrown if you start to get 'into' welding and/or want/need to weld steel thicker than sheetmetal. (yes, I know that the 125-140 class 120V MIG machines can weld thicker than sheetmetal. Somewhat.) But their main bread-n-butter use is on sheetmetal thickness mild steel. IMHO.
Thicker than sheetmetal uses? No brainer. Get a 240v powered machine. Something in the 180-210 amp class machine (Hobart 187 or 190, Lincoln 175 or 180 or 210/211 or Miller equivalent) can do an awful lot of welding.
To the OP. Want to weld 'almost' anything with GMAW? Get a 250-class machine.
Want to weld pretty much anything at home? Go for the 350-class multi-process machines.
Wait, maybe a Lincoln Air-Vantage 650!!! 4-cylinder 69 hp Cummins turbo diesel, built in generator (12 kw single phase or 20 kw three phase power) and built in air compressor (60 scfm @ 100 psi! No problem running that impact wrench now!

), 600 amps @ 44V DC output at 100% duty cycle.
It does weigh 2018 pounds though.
Don't ask about the price.
Oh, wait, that was last year's model.
Lincoln Air-Vantage 600's for 2016 seem to be all Deutz turbo diesel models. Only 64 hp now. But it is ~400 lbs lighter (1637 lbs). 575 amps @43V DC output @ 100% duty cycle.
The Miller or Lincoln 120-240V machines (Lincoln 210 Multi-process, Lincoln is running a $200 rebate, list price with rebate now $999) can do most 'home' welding. Look into those. Seriously.
