I work in the construction industry as an inspector. I have done so for over 25 years. Every job site I walk onto all I see is Miller blue. And I'm talking about every contractor with any welding. All blue.
I work with Coastal Steel regularly. Again nothing but blue. Atlantic Erection, Schmidt, Johnson Bros, etc.....all Miller blue. They must know something Bro.
It kind of depends on the process and technology as well. I'm a Miller fan myself, but do give credit where and when credit is due. There was a time where the Lincoln suitcase mig welders (that you hooked up to a multi-process machine) was the best, until Miller and the rest caught up.
For a multi-process machine, I'd go with Miller. If it was just a 120V, or even a 220V mig, Lincoln is just as good as Miller IMO. And so is Hobart and ESAB. Once you start getting up into the pulse spray, and such, that is where investing in a Miller really pays off.
Lincoln, Miller, ESAB and a couple others are always pushing the envelope technology wise, and it sometimes takes a couple years for the other Companies to catch up.
I've been to several Power Plants in the Mid West, East Coast and South, and have seen Racks from different places containing ESAB, Miller, Lincoln, and Thermal Arc machines. When I was growing up in a geothermal area in N.Cal every welding truck had a Lincoln Generator/Welder on the flatbed. This was pipe fitting and it was all stick welding and arc gouging, but it was rare to see a Miller machine on the back of a truck. That was over twenty years ago and now you see all kinds. Bottom line is, Miller might be the best at something today, but that doesn't mean their entire product line is the best for all time.
And, my Miller XMT304 CC machine is Grey. I bought it from a guy whose company he worked for wanted their Corporate Colors on the machine. At various Power Plants, I've seen Blue Lincolns, Grey and Black Millers, even a small rack Pink ESAB (I guess theft prevention?). I saw a rack of 12 multiprocess Thermal Arcs that were bright Flourescent Green. Sometimes what you go with depends on who you know that can cut you the best deal, and that definately seems regional. A good sales rep will carve out an area for himself no matter who he works for.
I'm a fan of Miller, but if all I want is a light duty mig welder, there are plenty of competative manufacturers that are equally as good and sometimes for less money. You certainly can't go wrong with Miller, but you do pay a premium, a premium that might not be justified.
It all depends on what you need it for. Will it sit on a shelf for most of its life, or will it be the life blood of your income.