Interesting thread.
Nine years now -- inverter (after two months) and turbo (after four years) failed, both under warranty.
Exhaust brake failed, replaced with PXRB.
Atwood water heater replaced this year. Amish CU for Norcold 1200. Coach water pump replaced. Now carry a spare coach water pump. Steps replaced, but that was operator error.:(
45,000 miles with usual maintenance. Minor fixes. Lots of upgrades -- TVs, satellite, TPMS, VmSpc. Airtabs. New Michelin XZA2's at 7 years.
With good maintenance (run at least monthly, 75 miles, run Onan under load, run AC, furnaces, water heater, refer, slides), should run XC without major problems. ISL and Allison 3060 running great.