I don't have a lot of data yet but on my Model S with range mode ON the efficiency is pretty good. Wonder if the Model 3 will have this feature in the future too. I'm ok if the power is reduced to the same as my Prius if I'm going to get more miles out if it. I know many people will find this stupid but if you don't like it then don't turn it On. Giving more options to all users is good.