So I just picked up my Insight 2 days ago. I have already driven 100 miles on it. First off I love it. I had nothing but fixed up sports cars before the Insight (first FWD and Auto trans in over 10 years!) I have been driving with the ECO button on religiously and have watched my MPG rising. I do a mix of stop and go on the way home, and flat out on the way to work. I thus far have an average of 45.0MPG. My question is am I really gaining or losing using the ECO button and also when the tank runs dry does the car revert to the battery?