Supercharged 7.3 gasohol F-250 4x4 towing 15K trailer etc

I will say that a 3.5EB should be more reliable than a supercharged 7.3. The 3.5 is designed to be a boosted engine with the correct compression ratio and it's pistons are similar to diesel engine pistons with steel liners casted in for the ring lands. The super charged 7.3 probably doesn't have ideal compression for boost and doesn't have steel ring lands in the pistons for long term durability.