Right now Cortana (Windows Phone) is the digital assistant that is furthest ahead.
And I laugh out loud whenever I see the add for Cortana on TV that gives the user the reminder that he has to leave now in order to get to his date on time.
The map shown on screen is of Richmond, VA, .. a city of 210,000 people
The route shows going from somewhere in Church Hill to the Fan .. about 3 miles
The time of day is around 8PM at night
And Cortana suggests that this will take 20+ minutes.
Sure, the map and the reminder are nice, but factually the trip duration is out the window unless you are considering driving during one of the 3 days in the year where there might be enough snow to impede you - in which case why aren't you at the supermarket, buying everything in sight like everyone else??