Some thoughts from an old hotrodder-----I have been building rods for close to 40 years, and all of the frame work I have done, from repairing, to boxing, to building complete frames from rectangular tubing has been done with an old 180 amp Lincoln AC stickwelder, using 1/8" rod, #6013, set on 115 or 130 Amps, depending on the thickness of what I was welding. I have never had a weld break in all these years, and these years have seen some pretty damn good drag racing with big engines. About 6 months ago I went and bought a Lincoln 110 volt mig, as I knew I would have a lot of welding to do on the sheet metal body of the roadster pickup I am building. This mig works wonderfully for sheet metal, but there is absolutely no way I would consider using it to weld chassis components with. Yes, it will deposit a bead of weld on anything that you want, but once you get any heavier than #14 gauge steel, you just don't get the penetration that you need in a chassis weld to take the concentrated forces that are applied to the welded area. This can kill you. In retrospect, I wish I had bought a larger 220 volt mig, because its wonderfull having no slag to chip, and very little clean-up, however my old 180 Lincoln buzz box still works great, and I couldn't justify the expense. About the plasma cutter---Yeah, they work great, but all they do is cut. If you have an oxy acetylene rig, you can cut, heat things, (as in removing frozen bolts), you can braze, you can solder, you can even steel wire weld, like us old guys started on years ago. If you have an oxy acetylene rig, they are inexpensive, and very versatile in a shop. If you have a plasma cutter, you are still going to have to buy an oxy acetylene rig to do all the things that a plasma cutter can't do. If you are running a production shop, where time is money, a plasma cutter is justifiable, because the cuts are so clean there is very little time required for grinding and cleanup. However, if you are a hobby builder, you will have to have an angle grinder anyways, and your time is essentially free, so you can spend a bit of time cleaning up oxy acetylene cut peices.