Thor is a huge RV umbrella corporation that has bought up a number of brand names over two decades or so and is now the world's largest RV manufacturer. You can double check but I believe most of their RVs are built in different plants or on separate production lines, similar to how Cadillacs, Buicks, or Chevrolets are built under the GM nameplate. As a result, there is not a lot of commonality amongst many of their RVs.
While I don't have any specific issues with my Thor Cougar, there is a lot of difference between a Cougar and say, for sake of discussion, a Thor Grand Junction. Two completely different FWs with totally different qualities. I believe the same applies to their motorized RVs so what might be done well in one plant under one brand name might not apply to all their RVs. As we all know, the entire RV industry seems to suffer from lack of overall quality. They continue to build many poor quality RVs, and still we go and buy the darned things anyway.
--2005 F350 Superduty Crewcab, 6.0, 4wd, short bed, 3.73 gears
--2016 Montana 3711FL, 40'
--SOLD 2014 Wildcat 327CK, 38'