Build Quality isn't horrible
My wife and I had the exact same concerns when selecting our next motorhome after keeping and upgrading from our ACE/Thor.
We went to multiple dealerships to check out the many manufacturers in our price range. Even a few above our price range. Fleetwood definately fell into the category of "you get what you pay for". Even within their own models and price categories, you can tell a difference.
I would never consider another THOR product after dealing with all of the build quality issues in our ACE. However, I wanted to see for myself if the Top of the line THOR product was better/same/worse. We toured a brand new Palazzo and found many of the same cheap hardware and build style that our 10 year old ACE had.
We only looked at new Fleetwood coaches in many price brackets and they start out with better products than Thor. The higher the price, the higher the tech and components.
If I could afford an American Coach, I would get it based on the quality of interior build. Those things are beautiful.
In the end, the Fleetwood Discovery checked most of the boxes for us. Good amount of tech, Freightliner chassis, 4 slides, decent build quality.
We have a short punch list of things that need to be repaired, but most of the items are cosmetic and not structural.
2021 Discovery LXE 44H - Freightliner XCM
2012 Thor ACE 29.2