I think the general guidance that some of us including probably you have said applies. There are good and bad of almost every brand since they are hand made and some individuals trash everything they touch! Like a house, there isn't a perfect one.
In an RV, I'd focus on layout which is kind of hard to pick without work, and how solid the basic structure is. I'd almost count on needing to do some work, but the price should reflect that. After reading so many stories and knowing so many people who've had to take new rvs back to the dealer over and over. I'll take my chance on used RVs and do my best to inspect before buying them.
Good luck in any case and make sure you don't filter your searches too much that you eliminate possible good units!