lincoln is a good welder butmiller is a lot better, for the biggest reason is it does not have preset amp setting, it has an infinite amp adjustment that you can change, up or down, as you weld...
That's funny, 'cuz the Lincoln out in the garage has continuous controls. You'll find that those features are model dependent in both brands.
...the 120v is the best all around welder because for one its cheaper than the 220v, second you can take it any place you want and plug it in. the 220 welds 1/4" metal. the 120v welds 3/16" metal, a 1/16" dfference , for the incovience and price the 220v doesnt make sense...
They both have their place. For basic use, the 110V units are fine, and have greater portability, but for heavier-duty use, the 230V units are better suited. The larger units, with their increased amperages, have no problem welding thicker plate. Not that such thicknesses are commonly used in automotive work, but it is nice to have the capability when needed.
In our shop, we have one of each - a 110V and a 230V - and a TIG. For most situations I use the TIG, unless I only need something quick and dirty, in which case I'll use a MIG since it takes less time to set-up.
...Most all body shops are mig only...
Any shop that is serious about doing high quality "body" work will be doing it with a TIG instead of a MIG. I'd bet that most shops that specialize in high quality chassis work predominately use TIG, too. I'm, of course, discounting places that cater towards collision repair where they try to get cars in and out as fast as possible.
Personally, I'd step up and buy a TIG first. Yes, it has a slightly steeper learning curve and is more expensive, but I think it's a better suited process for most automotive restoration work.
When it comes to brands; both the red and the blue are good ones. They each have their pluses and minuses. Tough to go wrong with either one. Don't count out some of the other brands (ThermalArc, ESAB, etc), either.