Sales: What sold us was that Farhad (Fred), upon checking out our furnace room in the basement pointed out two critical things: that we needed an air vent to the room so the water heater can work better and that we needed 2 pipes to the outside of the house instead of 1. As your average homeowner, we are no HVAC experts, so to have someone point out those things was really important, since it's not just about "buying a furnace and a/c".
Product: they use Lennox products and we opted for very high end since in the long run, it will be better. The furnace itself is much smaller than our old Lennox model and everything looked really neat and tidy.
Installation: the guys worked 10 hours without lunch/dinner until the job was done. They laid out out tarps to avoid creating a mess from the front door to the house, and they even suggested/helped us move the A/C unit in the backyard to a side location so grass cutting will be easier. They also showed us how to use the smart touchscreen thermostat afterwards.
Overall: it's been a month so far and everything is working great. Very satisfied.