New or Used HVAC Unit...

Hey everyone. I’m in need of a 10 seer or 13 seer HVAC unit, 2 ton BTU and I think I have located one. However, it is used. What are the risks or what should I look for if I use a used unit? Should I get a used one at all?

How big is the difference in price between the new one and the used one? How old is the used one? Any sort of parts/labor warranty on it or is it being sold as-is?

My gut just tells me to go with new if the prices are pretty close.