I have both a 24k btu kerosun and a 18k btu Mr. Heater propane. At this point I lean toward the propane because the flexibility with fuel tank sizes (from 1 pound bottles to 500 gallon tanks in the yard and everything in between). The fuel also does not go bad by holding on to moisture like kerosene, although five year shelf life on kerosene isn't bad. It's just easier for me to rotate my propane on a regular basis with the gas BBQ than it is to use propane for anything else besides emergency heating. For doing chores in the unheated garage in the winter, the propane heater is easier to use. I keep four 20 pound bottles and a case of 6 one pounders and feel comfortable that that's 1-2 weeks of heat in even the coldest weather. For my kerosun, it would take a 55 gallon drum to get two weeks (4 gallons per day vs. 2.5-4.5 days with propane). The Mr. Heater is also more adjustable and with D-cell batteries operating the fan, it really moves the heat around more effectively.
Now, with all that said, I have one cold room in my house that I struggle to keep warm on the coldest days of winter. For safety, convenience and redundency, I'm thinking of spending a few hundred bucks and getting a wall mounted propane heater
. I'll hook up a single 100 pound tank that should last me several weeks and it's operated on a thermostat, so it holds the room at a constant temperature, rather than the on/off (low medium and high settings) options the others offer. I might have to fill that tank 1-2x a year and my existing 20 pound tanks will still serve as a back up. With a 500 gallon tank, I'd be set for a winter's worth of use.
If someone in Colorado want's to come and remove a natural gas garage heater, I have one for the taking. It's installed (improperly), but doesn't look like it was used after it was installed sometime in the early 1950s. It was never vented properly and the only way to vent it properly would involve putting a vent through the new guest room addition we're planning. Somehow I think the wifey isn't going to likey that idear.