Escalators make people happy. They're ready when you are, there is almost never a line, and you can see progress happening the entire time.
Elevators are faster, particularly for long distances, but we get frustrated when we just miss one, and we often wonder when the next one is coming, even after a few seconds. (That's why lobbies have mirrors, to give you something to do when you're waiting).
The ferry schedule, invented by Cornelius Vanderbilt, is a third way to deal with transport. Instead of having each boat turn around the minute it arrived, he guaranteed when it would leave. We can build our day around a schedule…
[Or you could point them to the stairs.]
What do you offer your clients?