The spirit series has a steel construction with removable plastic work surface. The Genesis series has a Stainless Steel work sufaces, painted enamel hood and doors, 42,000 btu for 507inch grilling area compaired to 36,000 btu for 424inch grilling are on Spirit. That makes the Genesis a little less btu per sq inch of cooking area. A little cooler but not much.<br><br>Post edited by: coolhotsauces, at: 2009/11/22 19:36