Any article on anything to do with used cars at this point in time, should include the caveat that (in the US at least) this is a very strange year for used cars.

That said, I bought a car from Carvana a couple years ago, and the process was much better than one associates with buying a used car, generally. I think they have created an actually improved process/business, rather than just sucked up a lot of VC money to undercut on price. They are getting lucky with being in the used car business during a time when that is the hottest thing going, but they are also just better at it from the consumer's point of view, and it's not mostly about price.