Coachmen has sold a lot of C motorhomes into the rental market, where operators have enough experience that they will avoid products that have engineering defects or consistently bad build quality. I think complaints about RV problems represent a small proportion of the examples sold and in use. If anyone was building everything badly, they would not long be in business.
What is more important to a manufacturer's reputation is how well they step in to take care of the occasional problems, which are more often with purchased components than with basic structure. That would be during the warranty period, and if price preferences have you buying out of warranty, then warranty service is no longer relevant.
There are a few brands, mostly low volume manufacturers, that are consistently better in build quality, better in service and support, and even a few that build radically different structures from mass production C's (Coachhouse, BornFree, Lazydaze). Their methods are higher cost, and for something of equivalent size, price premiums might be 30 to 100% new, and tend to increase as the RVs get older because the buyers seeking these know their value. Note that for two of these three, slideout rooms are not an option; this keeps most buyers from considering the brands, but the manufacturers believe that slideouts are a serious enough compromise of structural integrity that they will not change the way they build a RV in order to accomodate the feature.
Off that soapbox. You have to figure out your price point, what you want with respect to layout and features, and shop for the model and age that meets your price point. If what you want is mass production, it doesn't matter a whole lot whether it is Forest River, Jayco, Winnebago, Coachmen before it was Forest River, Gulfstream before they got out of the business, or one of the several Thor brands manufactured by Thor's Fourwinds company before it got reorganized as Thor Motorcoach. All of these brands have been used in the C rental market, where value for money, and durability in hard use, determine what gets bought.
It is a lot like buying cars for use as taxicabs, or pickup trucks or vans for fleet use. A number of manufacturers produce adequate products at a similar cost. Ford, Chevrolet, Dodge, Nissan, Toyota all build something suitable. Somebody can find something to complain about in each. But they all get the job done.
Tom Test
Itasca Spirit 29B