I've managed to get by with an old school arc welder all my life--220V ones like an old Miller and Lincoln "Tombstone"--now using an Airco one I bought off craigslist for 50 bucks a "Bumble-Bee" one that's still 225 amps maximum output like the big ingots,but it is much smaller and more "portable" mounted on an old shopping cart base..
MIG welders are better ,make better welds easier,but also cost you more to buy,wire is higher cost than rods,and you'll need argon & Co2 to make good welds with one...the "flux core" gasless welders are more like a wire feed arc welder,and make similar welds to a stick welder,in my opinion they aren't much better than a stick welder,except maybe they can be turned down enough to weld thin stuff without blowing holes in it..
I like using the arc welders on thicker stuff,they penetrate real good and the welds rival MIG strength once your good at laying beads..
Its a lot tougher using an arc welder on sheet metal,and one wouldn't be a great choice for doing rockers or floors,but I have been able to get away with using 3/32" 6011 rods on thin stuff and once I got more practice,I was able to weld some floor patches in,but not in one solid bead,you have to weld in 1" or so spots,to prevent blow thru..
I welded some patches on my plow blade cut from an old home heating oil tank and the thin rods and low amps (about 45),seemed to be about right to allow a continuous bead to be laid down with no holes blown in the metal..
Since I do a limited amount of welding,I never did buy a MIG..but I have borrowed a few--I dont seem to do good with MIG's,maybe my arc welding techniques have to be "forgotten",the MIG torch handles a lot different than a welding rod..
I have borrowed a 90 amp Harbor Frieight wire feed arc welder from a friend to do rocker panels,and had a tough time not blowing holes with its flux core wire..I ended up using my arc welder..
An arc welder with DC as well as AC costs more,but is much easier to use on DC and gives you better control of the arc--you can reverse the polarity to reduce or increase penetration too....
Someone else more familiar with MIG welders will likely tell you that the arc welders are "antique" and useless in comparison,and they might be right--I'm not the guy to give opinions on a "real" 220V Mig with inert gases...never had much experience with them..