Our Carier Air V in our 2016 Carriage Carri-Lite is still going strong, fortunately. The tech may be saying this because of the interconnection with the furnace such that the one wireless remote controls both. I personally would not let that deter me from looking at whatever other brand AC may be available, but I would certainly go with a top line model, even if that mean re-wiring the furnace control to a separate thermostat. But then, I’m an electrician and that wouldn’t scare me. As for the AC feed cable, I believe it is 12/2 on a 20 amp breaker, so that should handle any brand of AC. On another topic, I recently installed a n RV Soft Start module that spreads the start up inrush current out over time, and that allows you to operate the coach on a 30 amp feed and even run two ACs at the same time. The Carrier AC unit is a little more efficient than most, and I found I could actually feed our coach from a 15 amp circuit and the AC would still start and run okay. Of recourse I just tried this to see if it would work; I wouldn’t try this at a campground unless absolutely necessary, and one would not want to have any other AC loads active in the RV.