Well, they are not all built the same. There are at least two basic construction methods in the mass market: laminated walls and stick built. I would rank Lance near the top of build quality for ultralight laminated wall trailers, and Northwood (Arctic Fox is their top line) for stick built.
But the best construction is unconventional and may be 2 to 5 times (or more) the cost of mass market methods. 1930's metal aircraft construction, only Airstream is still doing it, and doing more cheaply than they did in their best years. Welded metal frame, Holiday Rambler and Carriage used to do it, New Horizons still does (all builds are custom to buyer's design), and there may be other custom builders that might come back in if a buyer is willing to pay. Molded fiberglass hull, only Bigfoot currently building "Full Size" with large compacts from Escape and Oliver, if Oliver is still building. Oliver built a double hull, that puts them at the top if you can deal with compact floor plans.
But that's all "price is no object" which you did not qualify in your question.