TTs are built differently depending on the brand....some with aluminum studs and the smooth exterior, others with wooden studs and usually have the corrugated style siding. If you can check online, many manufacturers show a rough idea in their brochure of how their trailer is constructed.
Absolutely agree that you can, by luck of the draw, end up with a lemon from a company that normally turns out a great product. Frequent, routine maintenance is crucial no matter what you decide on.