I have a force 10 heater on a small 30 boat sailboat. It was originaly kerosene, but parts for the burner are very hard to find, and it flared and smelled. I converted it to propane with a kit sold by Sig Marine, the end result is the same as their Cozy Cabin Heater.
As noted above the best feature is the small size and 1" stack. Dickensons are much nicer, but in addition to being larger, having a big diameter stack, they also have a long minimal stack height. On my boat mounting options would be very limited and would require the stack to be way above deck. They also need 12 v power and the diesel ones need a gravity fed day tank or pump system.
I have had good luck with my heater, it draws well, will heat my boat on shoulder seasons just fine, and unlike just using your stove top, does not put moisture in the boat. Adding a 12 v cabin fan near by helps move the heat around. It will not heat the boat in mid winter even in our mild climate.
If you have the space and money go with a Dickenson or even better a forced air system (espar or similar), but for a small boat the Force 10 is OK.