I have been to the school, a couple actually, bought the book, read a little and all I know about metallurgy would be a short list. My experience and variety however is long, maybe deep too, I worked for probably a hundred different contractors and shops over 15 years, seen most of this every way you can do it and I look at others perspective but there is almost no common weld job as a diy that wants results,,, a specialized hobby or need is a different matter but for general **** from a lawn mower to your pickup it can be done with the compact mig,,, 99.5% and the other I would find a reasonable bud with a tig in the rare event you might actually use it. Even aluminum is rather rare,,, I have thousands of pieces so there is a need,, the 210 has replaced the tig but as a home brew scheme unless I had a burning desire wouldn't fart with it.
A 211 with 030 is hard to beat, done thousands and thousands and thousands of welds with one in that class, in between tig,,, cant even remember a general repair not irrigation related and as for paint or rust,,, its worth cleaning most of the time especially for hobby type jobs, its routine to scuff some paint or rust off, just do it.
I do use a few sticks and one reason is that its easy, don't have to move a machine to a piece of equipment for small work.
