As I've read the "What should I get?" threads over the years, the frequent advice when a guy is asking about a used vs. a new machine is to buy new so you get a warranty and service. This certainly seems reasonable, except for the tendency for equipment to be made more and more complicated with newer and supposedly better "features" and "user-friendly" gee-jaws that maybe are better for advertising copy than functional usefulness. This sort of thing is big temptation for manufacturers now that they can just add a chip or some extra programming and have a new "feature" to brag about.
Of course, there will be disagreement, and what is a gimcrack to an old man like me might be an improvement to others. But at least understand that the person(s) you are advising might want to know that the latest version of a long-established product might have changed in some important ways. I hope that the equipment experts here, when they are making equipment recommendations, will comment on any applicable issue of simplicity and toughness versus extra bells and whistles. (I recognize that you often do this, and appreciate it).
Equally interesting would be any suggestion of how an owner could make alterations in a particular model and year of welder to improve it. "Welder hot-rodding" might resemble automotive hot-rodding in which, for example, you might eliminate some piece of "smog-crap" for the sake of simplicity, or replace a restrictive exhaust manifold with a freer-flowing tube header for better power and/or fuel efficiency.
A couple of possible examples of "welder hot-rodding" (which just happen to be of particular interest to me!):
First, I have read that the MM180 offered better arc-starts than my MM175 because Miller had added a "run-in circuit." Is this circuit something I could add to my MM175? (I haven't got the wiring diagrams to compare the two machines because I just started thinking about this). Also, the MM180 was said to be a lot easier to dial-in (not talking about the Auto-Set option here) because it was a "constant wirespeed unit" where the MM175 was a "wirespeed tracking unit." Just from the sound of it, I expect that this is a more involved change in circuitry, but maybe you'll tell me different . . . .
Second, here's an actual example of "welder hot-rodding" (you don't have to accept this term, which may seem silly) that I did a few years ago. I was able to buy a brand-new Traffimet medium-duty spool gun and control box at about 20% of the new price because the buyer had tried it and been unable to weld aluminum due to the wiredrive ramp-up speed being wrong for the material. I phoned the Traffimet distributor in Florida and got a smart young guy who said, "Oh yeah, we know about that and have a new board for $60 that fixes it." He explained that where Americans tend to use spool guns more for aluminum, in Europe they are very often used for steel and stainless, and that the ramp-up was optimized for that. Very kindly, he told me that if I could solder, he'd send me a diagram showing the one resister that I could remove and replace with one of a different value, saving $60. However, I went a step further, and replaced the resister with a potentiometer, mounting it through a hole I made in the face of the control box so that I had a shiny black knob for adjusting the ramp-up speed to any setting I might want.
I expect that there is no end to the little upgrades that reasonably capable owners might be able to make to their equipment with direction from the experts, even if it is only replacing one resister or capacitor or whatever. I'd be surprised if Cruizer isn't doing alterations of this sort routinely when he overhauls certain machines for customers. Sometimes, as automotive hot-rodders know, a particular model of car will have a known chronic problem, one that can be permanently fixed with some alteration or replacement component, turning a bad car into a decent one. I'm guessing this applies to certain welders as well. (And again, I do appreciate that some suggestions of this kind have been made).