If the spin on fuel filter is a quality filter setup it should work well if maintained and will provide the convenience of a spin-on filter change. With that said...there is nothing wrong with using the OEM filter setup, which is what I am using/maintaining & works well.
The military spec'd the design of MEP generators to be able to use fuels that were readily available and stocked in their operations area & compatible for various climates as required. As civilians we have reliable access to the best fuel which is Diesel #2 Summer + Winterized Diesel if needed in your operation climate.
Here is a link explaining the different grades of Diesel. Personally I stay away from BioDiesel X% as much as I can. Here in OR B5 is the lowest % of BD we can use on road. Biodiesel is hydroscopic & reacts with various metals and does not store long term very well.
Here is a snip from another forum discussing Jet Fuels:
JP-4 is typically composed of about 50-60% gasoline and 40-50% kerosene, is highly volatile, and contains hydrocarbons in the C4-C16 range. JP-4 was the primary fuel of the USAF for decades; however, it has been phased out in favor of JP-8 (see below). By specification, it contains a full additive package including a corrosion inhibitor, anti-icing, and anti-static compounds. An optional additive is a metal deactivator. Compare to Jet B.
JP-5 is a low-volatility (C10-C19 range) jet fuel with a relatively high flash point (for shipboard safety reasons) and is designed for use in aircraft aboard Navy aircraft carriers. Anti-icing, anti-oxidant and anti-corrosion additives are required in the formulation of JP-5. An optional additive is a metal deactivator.
JP-6 used only in tests during the XP-70 program
JP-7 Not a distillate fuel, but blended from stocks...used for the SR-71
JP-8 was developed to be less volatile and explosive than JP-4. (Commercial Jet A-1 fuel is equivalent to JP-
. In 1996, the USAF completed conversion from JP-4 to JP-8 fuel. It also contains a full additive package including a corrosion inhibitor, anti-icing, and anti-static compounds. Optional additives are an anti-oxidant and a metal deactivator.
JP-8+100 is an improved JP-8 fuel with additional "fuel injector cleaner"-type additives. This new fuel has been demonstrated to significantly reduce engine and fuel system operation and maintenance costs for a variety of aircraft. The new additive also increases the thermal stability of the fuel. (When thermal stability is compromised, fuel breaks down into gums, varnishes, carbon deposits, and coke.)
