We are doing a transafrica trip with our 7.3 Powerstroke. Up to now 85000 km (around 55000 mls) only in africa with sometimes extremly bad diesel, lots of idling or very slow driving as the roads are no roads most time. But also hard acceleration in deep sand and mud. The rig is with 11500 lbs very heavy.
We are very happy with that engine. MPG is 16 in average with a gas engine would be half in that contitions. Except oilchange we only changed the fuel filter once (racor pre filter is installed). Never had an issue with the engine except a broken wire of the alternator.
I think it is not cheap to buy a diesel in the beginning but long term wise it is woth every cent you have to invest in the beginning. If you have longer trips you will spend a lot of money in fuel and with a gas engine it emty your pocket even faster
A big thing for us also is the range. With a gas engine you are limited very much. We never would be able to travel in remote areas here with ours without a range of less than 500mls off road. That means 1000mls on road.
The best thing we ever did.....buying a Sportsmobile with the 7.3
greatings from africa