I would go with the miller. I am a 597 union pipe fitter out of chicago. I weld all day long for 8+ hours a day, carbon steel, stainless, titanium, inkanyl, chromium, disimilar metals, you name it I can weld it and 90% of the time all the weld are x-rayed . If I were to buy a machine it would be the miller 330 xmt, it does it all soft and stiff stick, heli-arc (tig), pulsed tig, scratch start tig, lift arc tig and mig. It has a hot start feature infinate heat settings and is all digital. Runs off of 220 single phase, 220 3 phase and 480 3 phase. There is a place outside of chicago called redi-arc, and they have a rent to own deal, they have new and rebuilt. The company im working for had to buy a new machine and I turned them onto this setup, they bought the rebuilt miller for $1300. Granted you have to buy the mig gun and feeder but if you had that machine you could get the tig torch and regulator for alot less and have nicer higher quality welds. Oh yeah the whole machine only weighs 70 pounds. If this is out of your league I would go with the miller 175, it is a nice machine for the stuff we do, and if you cant fill the weld in one pass (which you shouldnt) just run some stringers, remember the root pass (first pass) is the weld that counts the rest is just filler metal. There hasnt been to many times that I have actually had to run a machine over 150 amps. Im not sure where you live but I have been shopping at BOC gases for a numerous amount of years and right around now (christmas) you can pick up the miller or lincoln 220volt mig welder for under $700 that includes welder, wire, hood and cylinder of gas.
Good Luck sorry so long.