Driver was on time and pleasant. The only reason for not giving 5 stars is he didn't drop us at the correct terminal. He should've known there was more then 1 United terminal we did not.
The taxi turned up early, which was great. My only qualm is that the driver charged us an extra 20 dollars for tips and tolls. I didn't see us going through any tolls, so I was surprised that we had to give him 20 dollars extra. If I used them again, I would check exactly at the time of booking what extra money should be given to the driver. Apart from that it was a great service, but do remember to ring up the day before your departure to confirm your booking.
The driver arrived early so we could get to the airport quickly. A great trip to JFK from our hotel.