Hi ... I have a diesel fired Rayburn Regent on my boat. It has a back boiler and provides hot water and heats a small radiator in the bathroom and provides background heat in the main cabin. It is rather nice, but during the Summer it does tend to get the cabin a bit on the hot side, so out comes the small gas burner to sit on top of the stove. The Rayburn is effective .. perhaps too effective at heating and could maybe benefit from having some more radiators attached to dissipate the heat a bit better. Cooking also needs a bit more planning as it takes an hour or so to get the oven up to roasting temperature, although the results are worth the effort.
All that said, I am sadly replacing the Rayburn later this year with something easier to use. The boat will be up for sale by next Spring and whilst the Rayburn is great, as the boat is currently a liveaboard, it will not suit everyone's needs. So the plan is to replace it with something more user friendly.
Just my experiences !