Was he enthusiastic enough to explain what the specific suspension enhancements were? Looking on their website, it appears that it's Bilstein shocks and a Helwig rear helper springs. They seem to talk about sway bars but they don't say that they have upgraded them over what comes on the OEM Class C chassis. My Winnie has rubber isolators between the chassis and house, I suspect most do. Any stretched chassis is going to have an extended driveshaft and it will be balanced as part of the normal driveshaft building process. If the chassis isn't stretched, it will have the normal OEM driveshaft that was balanced at the factory.
I wouldn't chose a Jayco because of their J-Ride if I wasn't satisfied with the floorplan, weight carrying capacity, or build quality.