A couple years ago we were considering buying an RV. We purchased a software program from a publisher in NW Washington (RV Consumer Group?) that is akin to the Consumer Reports for RVs. Big Foot was very highly rated as was, to my surprise, Winnebago. What floored me is that smaller is not better from the standpoint of stability and safety, there is a sweet spot for axle length and weight distribution.
I too live in the Willamette Valley where the building (including RVs) envelope is very important. For that reason I would lean to fiberglass as it can be mended by a boat yard.
We opted out because of the expense.