The one that takes a single propane bottle. The one problem with it comes in rough water. It has an tip-over shut-off mechanism. When the boat is rocking, it turns the heater off...even though the heater doesn't actually tip over.
I also have a Coleman "Black Cat." It doesn't have all the safety features (tip-over, oxy depletion, etc.), I now run it on the passenger side console and reserve the Mr. Heater for inside the cabin where the safety features are important.
Since the middle-rear curtain always seems to be rolled up, even in the worst weather, there is plenty of air movement in/out of the enclosed helm area that I don't worry about oxy depletion or C02 build up. The Black Cat is designed so that it is almost impossible to tip over in the roughest water.
In truth, all my trips to the CBBT in Nov and Dec the WX has not been below freezing. By layering clothing, wearing insulated boots with extra socks, and moving around with fishing, I've had to do little more than use the heaters to warm hands.
Dave