Personally, for me I'd much rather buy a new car. Why? You have the usual 100,000 mile warranty that goes with a new car. Sometimes more rarely less.
If you have problems with the car and the dealer refuses to help you, the manufacturer is 'Johnny on the Spot' with help. They will over ride any dealer on repairs that need to be made. They will also work as a go between with you and the dealer. if the dealer still gives you problems the manufacturer can and sometimes will pull their license to sell tat make of vehicles.
I'm not sure what make of car your looking for but i can tell you from dealing with them in the past The Ford Motor Company is a GREAT company for fixing issues. I have not had to call the other manufacturers. It's always been the problems with the dealers who sold the vehicles. FMC has stepped in to intervene. That particular dealership no longer is a Ford Dealership.
You can still make deals when purchasing a new vehicle. But whatever you do GET IT IN WRITING!!!
Do I sound like a broken record here? All the rest still applies...
Best of Luck in your search!