Research and read all you can. There's lots of info out there and the time you spend will pay you back. This is a great place to start. Many RVers would never buy a Thor product due to problems many have encountered. The counterpoint to that is that Thor sells more units than anyone else so you are naturally going to hear of more problems. After all, message boards aren't exactly a scientific study :)
Personally, I'm kind of on the fence with Thor. There is generally great value for the money, for sure. Any and all manufacturers churn out crappy units so RVs at any price point are kind of a roll of the dice. The whole rental thing is an interesting twist. I can see some benefit as the people were regularly held to a high standard of keeping it clean. One of my biggest fears with a used coach is some guy and his herd of dogs living in the thing for years at a time. That's pretty much erased with a rental.