Sounds like a win-win, MRB. My parents have/had three different Carrier central a/cs beginning in the mid 60s, all were wonderful and reliable. I guess they've given up on their signature round condenser unit, however (LOL). I loved as a kid standing over that big fan on top, even if it was blowing hot, nasty air. That thermostat is pretty cool (no pun intended).
76 is NOT air conditioned, LOL. That contractor would have been shown the door with me as well. Humidity does make all the difference. I live in a small window of coastal area in LA where a/c is not really necessary generally. It rarely gets above 80 here, and even when it does, it's not humid and a fan to move the air will suffice. In Minnesota, it's very humid, granted for a much shorter period of time than in the south, but I would not want to be without a/c for long.