The paper proposes a conceptual framework, linking value-oriented criteria, simulation approaches and knowledge sources, to support the value-driven assessment of Product/Service Systems in the preliminary product development phase. The paper describes the peculiarities of the Multi Attribute Decision Making (MADM) problem in the PSS domain, identifying relevant categories of criteria to guide the preliminary value assessment of Product/Service Systems. Each criteria has been analyzed and linked to the appropriate simulation method, and each method has been further associated to people/roles in the Virtual Enterprise who might possess relevant knowledge to populate the models. The value assessment of an aircraft engine component has been used as case study for the definition of the value attributes. The list of generic value-related criteria, coupled with the respective simulation approaches has to be considered the main result of the paper.