Have been FT for 2 years 07 Hr ambassador other than the nevercold just a few minor problems. I think you will find many choices in the brands you named in the price range you are looking at.
Miles don't mean near as much as care. A well maintained coach with more miles may be a better than a low milage rig with no service. Understand tire codes as if they are not new you should replace in these year ranges. Unless your comfortable an inspection is a good idea.
Also transmission and oil analysis from places like Blackstone can tell you whats going on the inside of the most expensive parts.
Good luck and keep posting or pm if I can help.
Jw