In this paper we have compared several policies for customer allocation in a G/G/n queuing system. We have put in evidence that manager's perception and customer's perception differ not only because time average and individual average are generally different, but because managers put the focus on mean sojourn time while customers rather put the focus on variance and fairness.
By the way, it has been recalled that the best choice depends heavily on the real life conditions : the efficient choice for centralized systems with timeliness of information is not the efficient choice for distributed systems with uncertain knowledge and conversely.