Kevin and Refugio
Good write-ups. Me, I like one furnace, one location, one fuel line and one intake/exhaust system. Also I like the ability via the engine rather than a furnace to heat coolant in the hydronic system when cruising. Dock sitting vs cruising time can thus impact pros and cons.
This past summer in AK we had a need to replace a simple electronic part in the Hurricane furnace and naturally did not have it on board. No problem as the hydronic system pumps and HXers kept things warm for 8 to 12 hours per day via the engines. Very helpful in Glacier Bay!
As the vessel and spaces become larger choices of furnace type may change. With hydronic the hoses and tubing act as radiant heaters throughout the vessel's bilges and ER space, another plus for hydronic IMHO. Lots of choices and I doubt there is one best for all.