Gasoline vs. Propane powered home generator?

What type of generator should I buy for my home, a gasoline or one that is powered by my propane gas line? Pros and cons of each? I need between 10,000-15,000 watt of power since I want to hook it up to my ac. Do they make 10,000 watt generators that are portable? Why would you need a portable generator? Thanks, moving to a hurricane zone and am unfamiliar with these types of products.