Work ow Management Systems (WfMSs) today act as ser- vice composition engines and service-oriented middleware to enable the execution of automated business processes. Automation based on WfMSs promises to enable the model-driven construction of exible and easily maintainable services with high-performance characteristics. In the past decade, signi cant e ort has been invested into standardizing WfMSs that compose services, with standards such as the Web Services Business Process Execution Language (WS-BPEL) or the Business Process Model and Notation (BPMN). One of the aims of standardization is to enable users of WfMSs to compare di erent systems and to avoid vendor lock-in. Despite these e orts, there are many expectations concerning portabil- ity, performance e ciency, usability, reliability and maintainability of WfMSs that are likely to be unful lled. In this work, we synthesize the ndings of two research initiatives that deal with WfMSs conformance and performance benchmarking to distill a set of lessons learned and best practices. These ndings provide useful advice for practitioners who plan to evaluate and use WfMSs and for WfMS vendors that would like to foster wider adoption of process-centric service composition middleware.