I guess your starting to see a recurring theme. And yes there is a reason for it.
About the best you can do is to find the floorplan you like/want and then determine what features and build level.
It follows a similar pattern to other stuff.
Interior;
Particle board with shelf paper on it to look like wood for doors and drawers, with particle board sides, stapeled together is the cheapest, and will fall apart the fastest,
from there the progression is roughly
Wood doors and drawer fronts and glued nailed plywood,
to hardwood screwed and glued.
Appliances are similar along the lines until you get to the top end.
Countertops are a good telltale, Solids being the better, particle board with a formica type covering being cheaper
Plumbing, plastic fixtures are standard and will be among the first things changed by new owners (showerhead especially)
Tank sizes determing length of dry stays/ boondocking, large tanks mean weight, which means heavier frames and suspension.
Exteriors, You seem to have already leaned toward azdel sided which is generally seen as preferable to tin and wood,
Single pane windows are the standard with insulated being a less common preference item.
Enclosed underbelly if you intend to camp in possibly sub freezing weather, or are concerned with travel in a lot of long term wet weather.
Insulation will be poor in all, you can only insulate 1.5 - 2" so well and still keep it light. (pick up a yeti cooler, it works well but isnt light)
So pick your floor plan, decide on usage, always with hookups, frequent dry camping, and then start narrowing down the cost and qualities you value the most and match that to the product line most closely matching it.
There are minor variations, but I think you will find this to be close with most.