We have camped for over 40 years, owning everything from tents, pop-ups, TT, fifth-wheel and now our first hybrid. All are built and assembled in a rapid manner. For example, using screws with a large thread pitch for fast installation but smaller holding power. All makes will have some vehicles built where installed appliances and/or devices fail.
That said, you should purchase from companies who have been around for a substantial period of time and who have a reputation of good customer service and standing behind their products and warranties. Your dealer can also do wonders when it comes to getting the factory to stand behind the product. If the dealer is "pressuring you" to make a purchase, that is a bad sign. A good dealer is interested in your complete satisfaction to protect their reputation.
We recently purchased a hybrid trailer and while comparing different makes, I looked at these things: size of fresh water tank compared to gray and black water tanks, how is plumbing and wiring installed under the trailer (will it vibrate or rub), is insulation installed where needed, are drain pipes braced, is there a rear bumper for carrying the sewer hose and is the bumper welded to the frame securely, are doors sealed well. Also, can I see the fresh water tank so I know how much water I have when the "idiot lights" fail (and they often fail), Is the awning attached securely and will it open/close properly, is the water pump loud, is there space for clothes (many RVs are short on wardrobes), is the medicine cabinet plastic or wood, are there adequate elec. outlets placed for our needs, are there adequate heat ducts placed for good ventilation/heating. I opted for a smooth fiberglass siding over a ribbed metal siding for easier cleaning, a curved roof for better drainage, can you get to the appliances and mechanics for service, does the water heater have a by-pass kit for winterizing. These are a few things to look at.
Our choice this last purchase was a Forest River Shamrock 19. We downsized from a 28' Jayco Qwest 5th wheel and reduced our weight from about 6,000 to about 4,000 lbs. I also opted for the Equalizer WDH with built-in sway control. I tow with a 2002 GMC 1500 Sierra and I've got sufficient power to travel to MT, CO, FL, ME, MA, MI,OH, IN, WI, MN, KY, TN, PA, NY, etc. I cruise around 55-60 mph and drive mountains in the truck lane. I averaged 12 mpg towing the 6,000 lb. trailer and am shooting for 15 mpg with the new trailer.
Good luck with your new purchase and happy camping.