In a given price class, there isn't much difference in any of the brands. The basic quality of construction and materials is driven by the target price of the unit. As UTTransplant says, the extreme price competition in the RV market prevents any inflated pricing for a given size and set of features. To make one model less expensive than another, corners have to be cut on components, materials and assembly costs - there is no free lunch here!
There are three major areas to look at:
(1) Running gear & chassis
(2) "House" construction and materials
(3) Appliances
1. You want a trailer chassis that is strong (rigid) with plenty of weight capacity (GVWR) for the size, plus axles & tires that are more than barely sufficient to carry the GVWR. So called "lite" models typically cut out weight by using a skimpier chassis, and lower priced models save on axle and tires.
2. The house can be anything from a wood frame with metal siding and a rubber roof to a steel frame with fiberglass sidewalls and roof. Generally, a metal frame and composite fiberglass sidewalls are superior, but there are exceptions. Some of the very best built travel trailers have metal frames with aluminum skins. This subject could be a lengthy topic all by itself (with many conflicting examples), so I won't elaborate here. Cabinetry is another area where the quality can be anywhere from cheap composites with vinyl surfaces to stained hardwoods. Assembly quality, i.e. workmanship, is driven by the time spent on assembly and that again relates to cost. Cheaper rigs have sloppy work under the covers, on the roof and most any place its not too visible. Last, the materials used for flooring and upholstery vary wide ly with cost.
3. The appliances are usually the easy part - they all come from the same 2-3 RV industry suppliers and the models are mostly equivalent. Fridges, water heaters, water pumps, furnaces and a/c units will be mostly alike. Just take note of features and capacities, e.g. is the fridge 8 cubic ft or 10, or the furnace 25,000 btu or 30, 000, or the a/c is a heat pump vs cool only.
