I'm British and prefer mpg. Why? Because for starters kilometres are alien to me, but also because it's just familiar and relatable. But with that said, the num

I'm British and prefer mpg. Why? Because for starters kilometres are alien to me, but also because it's just familiar and relatable. But with that said, the numbers manufacturers give are never even vaguely useful IMHO (my car is technically 40mpg but I get low 20s) so it's more for comparison of efficiency between journeys than anything else.