I’m an eco mode hound. I do a lot of highway driving for work. I can’t get a ticket. Cruise control and eco mode. Getting almost 24 mpg in the m40i in the mountains. 32 with my 330i. Sport mode only for twisty roads or road positioning to make exits.
I will leave mine on in town/village/country driving. In actually city conditions, well, sport mode disengages start/stop anyways! Hehe