Start pulling drawers out and looking at how they're built, stick your head in cupboards and behind panels, crawl underneath, look at the frame and axles how they're built and reinforced, open up every nook and cranny and look at it 360°, kick the tires, step on floor and see how it feels, get up on the roof and walk on it, push on the walls, check out the seams, the wiring, the gaskets and whatever. Run the slide in and out, turn on the water, check out the water heater, turn on the lights, read and inquire about how its constructed compared to others. That's how your going to figure out which are better then others. There is no substitute for doing your due diligence.
If you ask someone, they'll tell you whatever brand they own is the best (why else would I buy that brand).
In the end, you're going to have to decide for yourself how much you're willing to pay and how much quality you're going to get at that price. I may be willing to pay $150K for top notch quality that will last 30 years. You may only want or need something to last 5 years and only want to pay $10K. Everyone has different needs and wants. that's why they sell Ford Fiestas and Maserati's.
