Propane is often the cheaper option

In many places around the United States propane prices are significantly lower than gasoline or diesel because of local natural gas production. The price of propane and natural gas has also gone down while gas prices have gone up. 

Propane may also be more readily available, some cities and towns have propane and natural gas pipeline networks. The opposite can be true in other places, be sure to check the situation in your area.

You can store propane indefinitely

Propane can be stored indefinitely without spoilage, unlike gasoline and diesel which may spoil within a few months to a year, depending on the quality of the fuel. Some leakage may occur from composite propane tanks, but the stainless steel tanks available in most places are much more tightly sealed and don't really leak at all.

But before you stock up on propane, be aware that some states and countries have regulations that determine how much propane you can legally store. So be sure to check your local, state or national legislation.

Propane is more environmentally-friendly than gasoline or diesel

Have you ever had a propane cooker running in your house, or seen it at another house? Have you ever seen a gasoline or diesel cooker? Of course not, they release much more pollutants in the air and anyone cooking with diesel or gasoline would suffocate and die, and the food wouldn't taste very good. Propane on the other hand burns clean, is nontoxic and is thus much more environmentally friendly. Especially considering gas or diesel generators do not have catalytic converters to clean up their exhaust gases like cars do.

Propane greenhouse gas emissions are 1.55kg of CO2 per liter. Compare that to gasoline or diesel which release 2.31kg and 2.68kg CO2 per liter respectively.