Pretty much this ^. Once you get past the spark plug issue, the exhaust manifolds rotting off, and clickity clack, the damn things run practically forever. I have a buddy who runs a decent size lawn care business with 10 or so trucks and he looks only for 5.4 Superduty's for his fleet. He knows the inherent issues going in, but the longevity of the engines and strong trans in the SD's, they run forever. The truck around them falls apart from snow plowing before the engine or trans ever give out.