In Service Oriented Architectures, (Web) services are orchestrated in order to support business processes. An important issue, which is more and more addressed, is the Quality of Service of service orchestrations. Service providers publish their services with the QoS levels that they can meet. Service consumers choose services that satisfy the best the desired QoS levels of their service orchestrations. Therefore, service con- sumers need to know how much the service orchestrations satisfy their QoS expectations. In this paper, we present an approach based on workflow aggregation rules and Choquet Integral to measure the satisfaction degree of the service orchestration. The approach provides easy interpretation of QoS levels of service orchestrations. For this purpose, we present an accurate model of service consumer preferences taking into account preferential dependencies between QoS attributes.