If you look at the sales numbers of individual manufacturers, Thor, (Interstate), is either second or first in all types of RV's.
At least in the case of class B's, they claim they are second in sales. I say balderdash on that claim. I think they are including their so called B+ models in their numbers for B's, when they should be in the class C category.
I have no proof of this other than the fact that in the 8 years we've owned a class B, and would notice, we've only seen 2 Interstates out on the road or in campgrounds. We've seen many Roadtreks, Winnebago ERA's, and a few Pleasureways, Leisure Travels and Great West vans....