Welder recommendations

I am going to have to really give the Miller a serious look over, I know any day of the week a Hobart is a stand up machine. Would probably feel like a gift from God compared to my chicago unit from harbor freight.
I think we'll all agree that you will believe you died and went to heaven with a Miller or Hobart LOL!

As for the oxy to cut things, that is what I do and have a big bench grinder on a pedestal to finish things off, or a big electric right angle grinder. But is IS sloooow going to do the finish edging. (Never had a plasma cutter so can't pass judgement there.) I use air powered shears and nibblers for light sheet metal so your air compressor will be your friend there, as well as an air cutoff and grinding tool.

With a tapped power supply you can use gun orientation and speed to bridge the gap between settings, but that requires more skill than the average homeowner possesses.
And that is the key to have good variability in settings.... if you don't use one regularly, the tricks/experience like that are not in your repertoire.

If it has not been said, spend a few minutes reading up on the different gas mixes and when they are used.