A big advantage of a diesel generator over gas is that a diesel engine is more fuel efficient than a gas generator.The typical diesel engine consumes fuel at half the rate of gas . Therefore you have a fuel cost savings of 30% to 50%.
Another advantage is safety. Diesel engines are not prone to overheating and the fuel is not as explosive as gas. Always follow manufactures safety rules.
Longer life is yet another reason for you to consider a portable diesel generator. Once again the diesel engine does not have the overheating problems its gas counterpart does. A normal diesel generator will run for more than 2000 to 3000 hours before needing maintenance.