We bought a 2015 Expedition 38K in July of this year. As others have said, the chassis was basically perfect. The generator had tripped its circuit breaker, so the first time I went to use it I had no power and it took quite awhile to diagnose it because the breaker is on the generator itself and not on any panel.
The house portion had a number of issues: multiple AC outlets that did not have power to them on shore or generator; wall panel behind midship toilet was not fastened to studs and came completely loose; several cabinet doors over the dinette were not aligned properly and one had the hinge fall off because the screws were not installed; a heavy object was left underneath the bottom panel of an overhead cabinet which rolled around and made a lot of noise when in motion; a loose fitting on kitchen plumbing caused water to drip in the cabinet below; the park cable TV wiring did not work; Lens was missing on outside security light.
There were other things, but you get the drift. None of them were killers but they taught me a couple of important things about PDI:
1. Check every AC outlet with the coach connected to shore power.
2. Disconnect shore power and repeat the process with generator power.
3. If at all possible, plan a 1-2 day camping trip near the dealer's facility to find the bugs, and schedule a service visit for the third day to fix them.
You'll note in my sig that we did not keep the Expedition but traded it in for our current rig. This was based on a couple things, most importantly our distaste for the L-sofa, the extremely small size of the rear bathroom and shower, and the driving characteristics of the coach in windy conditions vs. a tag axle and Newmar Comfort Drive. Quality control was a contributing factor, but not the biggest one.
Hope this helps!