The second half of that equation is the run in adjustment. Not only does the machine give the initial seconds of the weld a higher amperage than the set amperage (hot start), the machine slows the wire feed down a good bit, so it doesn't try to build a lump while the weld is still cold/in the process of heating up.
Don't get me wrong, I'm not trying to say MIG is better than TIG. I've spent a heck of a lot more time under the hood with a TIG torch in my hand, than I have with MIG, as much of the work I do caters more to TIG than MIG. But, there are times where MIG is just flat out better. Doing certain long seams (especially butt joints or the likes, where there is no inherent rigidity in the shape, as an outside corner might have), the increased overall heat input will warp the snot out of what you are working on. Or, even in simple things like a 90 degree fillet in .100 or .125, pulsed MIG will produce a weld of very similar quality (appearance as well as function) as TIG, in a fraction of the time, which in my book, will qualify it as better for that application.
And yes, TIG is infinitely more versatile. With no more than pressing a few buttons, I can go from welding aluminum, to steel, to stainless steel, chromoly, and so on. MIG certainly can't do that. But, for production work, or just a larger quantity of new fabrication on material over .125 -.187 or so, I wouldn't want to be without a decent MIG, no doubt about it.
