First engine type/drive:
I have had I/O, outboard & now straight drive diesel.
With the proper transmission you can get a trolling valve for the trans. It bypasses fluid in the trans to slow prop speed while engine RPM stays the same. No more kicker. Dial-in a very precise trolling speed. Make sure the tranny can accept a trolling valve.
Straight drive versus v-drive will determine where the engine is located. I prefer straight drive as the engine is located more forward; best for balance sea-worthiness. Probably mechanically superior. Size of boat will determine if there is room for straights. Mine is 33ft with twin 200hp Volvo's.
Having no engines on the transom is awesome for bringing-in fish.
Maint is easier on the outboards as they are exposed. Diesel engine is more complex (such as a turbo intercooler), but fuel economy is 33% better. To get low noise odor-free operation, you need a newer direct injection diesel. Oil change on any inboard is a pain. Diesels have two stages of fuel filters to change.
Longevity of lightweight high RPM diesels is over hyped (what isn't these days); to get the long life of 10K hours you need to run them at around 1K rpm below max rpm.
Another advantage over an outboard is that you can install aa external Balmar voltage regulator & "smart Charger" that will charge both a deep cycle house battery & a dedicated starter battery at the same time without any mickey-mouse switches.
You also have a great source of heat & hot running water.
