Miles would be my preference but I don't have a speedo or computer. So for now I describe my rides by landmarks. "I rode to the river bridge on 44 then down past the Rock hill church then over to the back road to town, through town on main then across the big bridge and back to the house.
I think it impresses my wife much more than if I told her, "Well hon, I rode 10 miles today." It sounds a lot longer my way, so I may just stick with it for a while.