Conventional workflow functionality like task sequencing, split parallelism, join synchronization and iteration have proven effective for business process automation and have widespread support in current workflow products. However, newer requirements for workflows are encountered in practice, opening grave uncertainties about the extensions for current languages. Different concepts, although outwardly appearing to be more or less the same, are based on different paradigms, have fundamentally different semantics and different levels of applicability – more specialized for modeling or more generalized for workflow engine posit. By way of developmental insight of new requirements, we define workflow patterns which are described imperatively but independently of current workflow languages. These patterns provide the basis for an in-depth comparison of 12 workflow management systems. As such, the work reported in this paper can be seen as the academic response to evaluations made by prestigious consulting companies. Typically, these evaluations hardly consider the workflow modeling language and routing capabilities and focus more on the purely technical and commercial aspects.