My old motorhome had the original Duotherm in it from 1990. It worked perfectly. A couple of summers ago we were camping at the beach and it was hot, hot every day. The static temperature in the campground. That old Duotherm kept the inside of our old motorhome ice cold all day, every day. Granted, it was a 1990 model AC unit and most certainly made in the USA.
I put a brand new Carrier on my wife's grooming van that lasted about a year and a half. When it quit I bought a scratch-n-dent duotherm from Adventure.rv and it worked great till the day we sold the van and I would bet it's still going strong. As far as noise I could never tell that one was louder than another. I suppose it's possible but, I wasn't paying attention.
I once bought a Coleman AC off of a wrecked class B. I installed in on the van I converted to a camper then, when we sold that I put in on the cabover camper we bought. It was rock solid reliable.