My driveway heat transfer fluid was made by KOST USA in Cincinnati, Ohio, USA. My driveway contains 2,000 feet of 5/8" PEX tubing, and about 20 feet of copper, and a small heat exchanger, stainless steel, in the heater. It's not a fair comparison other than the degradation of inhibitors which happens in automotive applications as well as in others like the driveway. It was never my intention to use Evans in my driveway (I've already invested in the 31 gallons of custom mix for this application, "lifetime").
I hear what you are saying, but pure PG antifreeze retails for less than $20/gal; pure EG for about half that, give or take. So, I have a hard time "making the walk" to $40/gallon, considering the composition. What you are saying about the Evans product would hold mostly true for pure, no water added glycol fluid blends. When one buys this in automotive, it does contain inhibitors for the automotive metals and systems. So how much better is Evans than pure Sierra PG, or any pure PG, or a home made mix of PG and EG automotive antifreeze with no water?
I would think moving to a pure glycol coolant like Evans or another would be best indicated on a "new" system, where don't have any corrosion in place, your radiator isn't plugged with gunk, and all your metal parts are in as new condition and you keep them that way--like after a fresh rebuild, and after the radiator is boiled out.
It is helpful that you participate here, and thank you for the comments. Too often firms don't bother to tell us about their products and the only way we all learn is by an exchange of information.