Difference between super duty and power stroke?

Easy one first - The Ranch King is just a trim option. One reason to get the super duty is you can maybe use a 3/4 ton SD instead of a 1 ton standard. The taxes on a commercial truck are based on it's GVW, so smaller is cheaper. The diesel engine is better suited to pull/haul then a gas engined equal sized truck, but they are more $$$ & heavier, so it's a value judgment as to which one you go with.