We had a great experience with Discovery Mundo airport shuttle. The drivers were waiting for us at the airport when our flight arrived and our trip began smoothly. The driver offered to let us plug in our ipod and enjoy our own music, which was a nice perk. Because we had pre-paid through the service, there was no hassle to pay (other than tip, of course). The drivers were waiting for us a few days later when our vacation had come to an end. Definitely recommend!