In the active Fleming thread a recent fire took down a diesel F55 in NZ. It would seem lack of maintenance and electrical issues are normally the culprit in fires.
With diesels outnumbering gas on TF by at least 10:1 the answer between the two is obvious. A read of Boating magazine and a trip to your local rack storage site will yield a 10:1 margin for gas.
It all comes down to your boats mission. If one chooses to do what most of us long distance cruisers do, hauling what amounts to a house around, the answer is diesel. We spent decades boating inland, gas vessels are the norm by far. Cruising salt water and longer trips diesels reign.
In my younger days I sailed out of Manhassat Bay Long Island. The Atomic 4 gasser was the norm SV auxiliary. Once small but heavier diesels became common their greater weight required a redesign of keels and ballast locations. With diesel's better economy sailing became less common in light airs and the term iron maiden became apt.
In the PNW sail boats with no sails up are the norm and a very efficient way to get somewhere given their slippery hulls. So for a boat of choice and frugal expenditures many boat owners prefer sail boats. These types have their own popular forums.
Not to mention that ocean crossers are seldom power boats and mostly diesel powered SV. So, back to the OP's mission