Although they have a phone and internet there is no guarantee the gps is working/on. I've had an uber that took a long time to arrive due to incorrect gps and then I had to give them directions on the way, they must have been using wifi/cell tower positions as the location on the phone was wrong and jumping around.

Was this one of the green cabs that service the outer boros? If not, normal cabs usually concentrate on Manhattan and have only basic knowledge of everywhere else. It's helpful if you know the name of the neighborhood you are going to as well.

It was a yellow cab, but you make a good point - we were going to the Bronx, a bit east of the Zoo, which is probably not a very typical destination.