My opinion as a original owner 2001 4.6 with 250,000 miles on it. Assuming the vehicle hasnt been previously wrecked, I think dependability rests on 2 things location and preventive maintenance. Living in the southeast, we tend to put many miles on our vehicles but they are not subjected to the horrors of road salt that destroys structural,electrical and mechanical aspects of a vehicle. My 2001 doesnt have a speck of rust on it and still running the original exhaust for instance. Preventive maintenance wise, ball joints, tie rods, shocks, spark plugs, coil packs, brakes, coolant flush every 20,000, trans flush every 100,000, oil every 5000, PCV valve and hoses and 1 fuel pump. Still running original radiator, water pump and air conditioning. Not bad for 19 years old. I consider the gen 1 Expo simpler and therefore more reliable than a gen 2. 139K is just getting broken in.