regarding the varying methods and materials used in construction of the different brands of RV's, I would suggest new or soon-to-be new owners do a LOT of homework.
Read as much as you can find, and take anything that is said by the individual manufacturers marketing department with a grain of salt.
Accurate info is out there. Buyer beware as always is the best advice.
I have yet to see any "one trailer" that has what I would consider all the best attributes. You have to make some choices and accept some compromises.
It also helps to have an understanding of production processes and how companies save money in building their products.