It is not going to matter what you purchase as they all have their problems. I remember one time when my coach was less than a year old and I was in Junction City having a major slide problem fixed. There were 20 sites for RV with electric only. There was everything in there from a pop-up to a Prevost and all where having something Fixed. Plus there was a no-hook-up area with 20 more RV's waiting for parts.
Speaking from experience with a Winnebago we have had many issues with ours. Others have had good luck.
As for Thor, we have a few friends with that coach and they are having problems.
Some additional information: A friend has a new Thor Tuscany. As he was driving down the highway in rain it started coming in from the top of the windshield. The problem was that the manufacturer never put a seal at the top of the windshield. This same Thor, brand new, had problems with the water pump not working and the ice maker not working. Problem with the pump was the connection going to the pump was not on tight so it just sucked air. The problem with the ice maker was that the valve was hidden (also sittin over an electrical outlet) and when turned on the fitting came off and squirted water all over the place.
Quality control at many of the manufactures, not only Thor, are very lacking. Someone once asked where the antenna cable was in the roof and the reply was, "It depends on which fine craftsman threw it and on what day of the week."
Consider purchasing something between 1 to 2 years old and the previous owner should have had the major bugs worked out.
As you most likely know, it is a rolling earthquake going down the highway.
p.s., Welcome and don't pay no never mind to what Ken says. He really is a nice guy but please don't tell him I said that. His head is to big already.