My friend owns a propane company. His generator that he just finished putting in- the following week we got that Isaias storm, and his generator ran for over 60 hours. He said switching it from propane to NG is just the flip of a switch. I'll probably get one soon, as I'm on NG, but having the ability to have him bring a propane tank and switch over in case of NG shutdown(I'm very close to the coast) is a huge plus.