If you have laminated walls, you have to be diligent about maintaining all the lap sealant. A thorough annual inspection and a little work where needed can prevent expensive delamination repairs. The Minnie is our first trailer with laminated walls, so I do wonder about the long term. On the plus side, we're able to keep it stored inside all year long, so the roof and sealant doesn't suffer from much UV and weather exposure.
On the flip side, with aluminum sided trailers, it seems that it's easier for water to leak into the wall space and not be noticed for some time. So, whether you have laminated walls or aluminum clad, all you can do is be very diligent with inspections and sealant repairs.