The main differences are: Power output - Extreme has higher wattage capabilities, up to 10000W+ Fuel type - Extreme offers gas or propane, standard is gasoline only Noise level - Extreme runs quieter, around 48-67 dBA Vs. 60-75 dBA for standard Features - Extreme has more tech features, displays, and convenience add-ons Cost - Extreme generators have a higher price tag than standard models