We have an older Jayco, see Signature. It's a very entry level coach, and I think the Greyhawk models of that year were built differently and probably a little better. The rubber roof has been a problem. It also has the haphazard wiring and plumbing that seems typical of most mass production RV's. The interior has stayed together and the E450 chassis has been reliable.
Some of the new Jayco models are on Chevy 4500 according to their website. I think Jayco has good floor plans, and the J-Ride package, particularly the Plus version, is noteworthy. We don't have a fiberglass front cap, either. A Greyhawk with both fiberglass roof and front cap would be worth looking at. Remember, Floor Plan Rules. If the whole crew doesn't agree on the layout, no amount of engineering will make up for it.
I have NOT looked at this on Jayco, but I can say that some manufacturers build their coaches much differently than their towables. The linked complaints above are mostly about trailers.
To my knowledge, only Winnebago COACHES are wired similarly to automotive. They are also the one with the best parts support. That's important to me, but DW wanted the Jayco floor plan. Note: Winnebago TOWABLES aren't Winnebago-Built or -Supported. They've licensed the NAME to somebody else. The towables may be OK maybe not, but they seem to have about the same assembly techniques and product support as most other trailers. From a quality and support view, my choices would be
Clear Leader: Winnebago Coaches
Second: Jayco, Forest River Sunseeker/Forester
Last: The Others...Coachmen comes to mind
Ultimate Choice: The one the Mrs. likes best