I have a '98 Coachmen class C. It's undoubtedly built to a price point, but within that constraint it seems to be pretty well designed and put together. The cabinetry materials are plain and fairly lightweight (thin plywood, vinyl-wrapped particle board moldings, cheap pine scantlings, etc.) and the fit and finish is a bit loose in places, but they're structurally sound and function fine for their intended uses.
The wiring and mechanical systems appear generally well designed and neatly constructed. The wiring is neatly bundled together, wire nuts are taped so they don't come loose, and wire coloring by circuit is pretty consistently followed. The plumbing and ductwork likewise is put together pretty solidly and neatly. There are access panels to get access to most everything that might need it.
I would appreciate having more technical documentation (wiring diagrams and the like). Possibly they are available separately; I haven't checked. On the whole, though, I don't have complaints about their quality.