Like Veebyes when were were looking at new 5th wheels I would crawl under them and look how they were made.
At a RV show I ask a young salesman how well the trailer was built, he said let me show you, thinking he was going for the door I was surprised when he got down on his hands an knees and said "take a look at the bigger frame and the springs along with the Dexter 7000 axles" He also explained about the underbelly instillation and the water drains an a few other points even before we went inside the 5th wheel.
That whole day he was the only one who did this, other salesman didn't even think about showing me the under side of the their units, they always went for the door to go inside. I am not talking about low end units, I'm talking about the upper end units of $100K that think they are so great...
We went back an bought the unit the young salesman showed us, not because of what he did but because of how well the unit was made, not much bing or glitter but what it was well built with no press board, no plastic slides on the draws, lights that were well placed and not for just show a glow and it was priced well below those $100k units with all the same features they had...
Have we had some problems, yes, but they are minor an I was able to fit them myself, like any trailer rocking an rolling down the road you will have some minor problems from time to time and as well stuff that needs tweaking to make it your own.
When we did our PDI it took over 4 hours, I ask for a creeper, the tech said he had work there over 6 years or more and I was the only person he had did a PDI with that had ask for a creeper to look under a trailer. He also said I was one of the very few that had turned on all the Faust's and shower at the same time to see if there was any leaks under the sinks an shower an the bottom of the trailer :)