Jayco, what does the dealer know that I don't know?

I wouldn't shy away from either, but its hard without a tangible bag of proof that a keystone fifth wheel is any better or worse then Jayco. I'd go with the floorplan you like, even if that requires an order. The Jayco does afford you a two year warranty. I've also found the structure in Jayco to be very sturdy compared to others, typically using plywood in place of OSB or laminated wood products.