For the Ecomodder, very little. Actually, I like it better, as it's a touch smaller and has a nice MPG graph that the others don't have. Scan Guage II has some horsepower stats and other performance stats is shows. That's really it. This unit DOES change colors to match your dash lighting, which is neat.
See comparison link form SG site below...
Compare the Features of the ScanGauge products : Linear Logic