I wonder if it will have interactive verbal capabilities so that it can ask and answer questions. It would be awkward for some people who know where they're going but don't know the address to get in and realize they can't verbally guide the car ("turn right at the next light, go two blocks"), and also awkward for people who change their minds about where to go in transit. Also I hope it can deal with mistakes, such as telling it to go to Elm St. when where you really need to go is Elm Ave. If the destination you had in mind is 5 minutes away and it begins a route that is 50 miles in another direction, I hope you'd be able to a) cancel and reassign the destination, and b) maybe tell the computer before the trip the estimated travel time so it can tell you whether it's ETA is similar to yours. For people with a terrible sense of direction or who don't know the city well, if it starts going the wrong way it might be quite a while before you realize there's a problem.