My view of the express train is that it is only quickest if you can catch it right after you arrive otherwise I have found the limousine bus to be consistently the fastest as they seem to depart relatively often. When you start adding up time waiting for the express train, the subway, walking up stairs etc.....I just never found it saving me enough time to take it instead of the limousine bus which drops me off right at the door of my hotel. Maybe it depends on which location you are going to.