Our driver was waiting when we stepped off the train so we never doubted our scheduled transportation. He walked rapidly to his parked vehicle seldom checking to see if we were close behind. My husband and I are fit individuals but it took effort to keep up with him as he weaved through the crowd. Being an outgoing American I would have liked a little more exchange of information or conversation with the rdriver as we went through the city but otherwise I have not complaints.
Excellent driver! Very timely and got us to the train station in good time. Also provided us with directions in the train station. I highly recommend using this service for transfers to the Wien Hauptbahnhof.