When I was considering the various fuel sources for the Dickinson Newport bulkhead heaters, I contacted them directly and discussed options with one of their techs. I was intrigued by the solid fuel (wood, briquets, pellets, etc) heater. However, I was advised by Dickinson that this version is not recommended for serious heating of a cabin. It's intended more to take a slight chill off, and for ambiance.
For true heating purposes they recommended the diesel or propane version.
We went with propane, for a variety of reasons. Be advised that the diesel installation can be trickier, since the flue length needs to be greater to achieve proper draft. In most installations on mid-size boats, this effectively means the flue will protrude higher above the deck.
Some discussions of heaters here:
Cabin Heater Type and Arrangement
I'll try to find some more links of earlier discussions, too.