We had a wonderful experience renting with Sixt. Especially since we had to change our flight schedule. When we got to Sixt which is across the street from the rental car center (make sure you ride the rental car shuttle to the center and then take the Sixt shuttle in the taxi zone to get to their center across the street). The only complaint I have is the confusion on the website about how to get to them, we had to ask where to go but it wasn't too difficult!