I've never owned one, but we have very close friends (full-timers) that did, and they said they'll never go back.
Buying a 6-year old Thor product is kind of like buying a 6-year old Fiat 500 or Mitsubishi Mirage. They're pretty much spent by then. Our friends had issue after issue with theirs, and they actually bought it new (kept it less than a year, then unloaded it).
Personally I'd look for a brand with a better reputation (Newmar, Winnebago, Tiffin, etc.) If you're trying to stay within a specific budget, you might need to look at one slightly older than a '15 or '16, but in the long run I think you'd be better off.
Let's see what others have to say.
Happy travels!
. . . never confuse education with intelligence, nor motion with progress