We've owned 3 popups and 2 travel trailers. We bought the first popup used. After that, we've purchased new units. Since we plan to keep an RV for 8-10 years, I prefer to buy new. But, if I would never rule out buying a used unit if it was a unit we really wanted.
There's no question that you can save buying used, so the decision depends on the purchaser's personal financial status. If I were looking to buy a much more expensive RV such as a motor home, I'd definitely look for a used unit due to financial considerations. And, it's why I bought a used truck....almost like new at a lot less cost.
Once again..."different jokes for different folks!"