In general there are some risks buying from auctions. I like to buy from auctions not only because it is cheaper but also because it saves time. You don't have to drive around to see different dealers or private sellers. You don't have to negotiate with the sellers.
The place I bought my cars does not allow test drives but you can preview the cars the day before the auction day. You can turn on the cars. You can take the VIN numbers from the cars and do a CARFAX search. If you are willing to pay $500.00, you can return the car within three days of the auction.
Two of the cars I bought were under manufacturers warranty. The other cars were 1 to 4 years old when I bought them. I have not had problems with any of them.
The auction I bought from is so called "public auction" meaning any one can bid. There are some auctions that only open to dealers. I general, I pay about the same price as private sales of the same vehicles.