We have a '15 28QB on the GM chassis. We also bought it used with about 17k miles. The layout works for us but, may not be ideal for everyone. The handling and ride is every bit as stable and comfortable as we would expect. Fuel mileage is around 9 towing a 3800# car and hovers around 10+- without it. Tank capacities are very respectable. We will be replcing the single 12v battery for two 6v units this week. The 12v has met our needs thus far but would like a little extra so we can take advantage of some off grid camping.
So far we have not had any issues with the unit itself. When we purchased it, the instrument cluster was flaky in that it would just shut down after a few miles and then come back on a few miles later. GM found a "loose wire" and repaired that under warranty.
I'm still playing around with air bag pressures. As we have it loaded, it seems to respond well to 20# in both bags. 30# seems to make the ride a tad bit more solid.
Feel free to ask any questions...
Gary
