Buying an RV is not like buying a car. If a salesperson or seller tries to make the experience like buying a car, odds are they are hiding something. This should be more like buying a home.
When purchasing a new RV the first thing you should do is spend time researching different brands and models. You can find a lot of information online about peoples experiences with their RV’s.
When buying a used RV, it's usually less about the brand and more about how it has been maintained. This is difficult to determine sometimes if you aren’t an RV professional.