Gas generators are generally more portable than propane generators. That is because a propane generator must have an external tank hooked up to it like a gas grill does. Propane generators are generally bigger and heavier than gas generators as well.
Depending on where you are, the price of the fuel varies a lot. A gallon of gasoline puts out 125,000 BTUs, so to save money propane has to be 30 percent cheaper than gasoline.
Propane, like most compressed and liquefied gases stored in canisters, has a long shelf life. Gasoline left in a generator tank will break down.
Propane burns cleaner than gasoline. Carbon monoxide emissions are 20 to 40 percent lower than gas, but propane puts 10 percent more methane into the air. Propane is also non-toxic and doesn't produce harmful spills.
Gas and propane generators are equally noisy. Contractor's generators are frowned upon because they are the loudest and are disruptive to other campers.
