You will find many opinions as to what is best. I believe Fores River and Thor are large manufacturers with Forest River having bought out many manufacturers. There are also several manufacturers that build what would be described as top end units also.
If you are shopping used and you say do your research, I would say the number one issue no matter who built it is water damage. It's the number one killer of RV's. From there it gets into how it was taken care of, how it was stored. As far as water heaters, frig, furnace, ac, etc a lot of the stuff is all the same. Some people like stick and aluminum sides, some like aluminum and filon sides.
I compare it to buying a used car. I want the best looking/maintained one in the given price range so that if I do end up putting a transmission in it I'm not putting it into some clunker.
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