One piece molded body and if you can afford it, Coach House. Panel type construction check out Nexus, what sold me was the light weight steel frame which is stronger than aluminum. One piece WRAP around the edge fiberglass roof, no blobs of caulk at edges like the others. Steel truss construction close to 6" at center and tapers to about 2-1/2" at edges, very strong. Which means it has more space for insulation and less heating and cooling loss. One piece front fiberglass cap, no seams for future leaks. Flush floor slides.
If you are looking for a 4 season MH, look at Triple E Regency GT. They are good to -20 C (0 F), and have many very good features for both summer and winter. They are also very high quality, made in Manitoba by the mennonite community there.
jr consumer resources puts out a yearly rv review and also has info about rv construction. i found it helpful when researching my purchase. But research is the best answer, dont depend on the dealer. Lots of info on the internet. It was interesting that the econonmic crisis of 2008 caused a big consolidation in the rv manufacturer market, so a lot of rv brands are actually under on e big manufacturer like Thor. I think coachman is one of those brands that was purchased by Thor. So was four winds. Its like GM making chevy, saturn, olds, pontiac, etc. or Ford making Ford, Lincoln, and Mercury, all versions of the same product. Winnebago and Coachman are under different manufacturer umbrellas.
From my research when trying to make my own pruchase, between Winnebago or Coachman, I would choose Winnebago. The higher end class Cs tend to be Lazy Days, Born Free, and Dynamax by Holland, but price is higher.
Nexus is a new factory direct rv. there are no dealers. you buy right from the factory. I would check to see if a local dealer will work on it for you before purchasing or whether you will have to return to the manufacturer for any work. I cant see why a local dealer wouldnt work on it since most systems are the same but some local dealers wont work on brands they dont sell. I dont know that the price savings was signficantly more than buying from rv direct or a larger dealer. I have no financial interest in any of these. When I was purchasing my RV, I was initially looking at a class B and my local dealer which has a large service department said they couldnt work on it, and I have yet to see a class B in their shop. Additionally if you didnt purchase locally and they dont sell your brand, you may have to pay up front for any warranty work rather than having the dealer get paid from the manufacturer.
Winnebago , if my choice is between coachmen and winnebago and , have looked at a lot of Rv's in the past few years and winnebago seems to have the right formula for a quality unit at a price that is within the range of lessor RV's, that and I really don't care for coachmens parent company, Forest River.