The sustainability issue has gained importance during the last two and a half decades, starting with the UN Report “Our Common Future”. As the transformation to a sustainable economy is far from being an automatism, instruments to foster sustainable development are required. This demand has lead to a frighteningly high number of instruments. This paper introduces firstly, the concept of a comprehensive management system of sustainability in larger forest enterprises. After an introduction of the normative framework, the need for a participatory approach is described. The need for the use of different instruments is derived from the existence of various subsystems (Manufacturing / provision of services, Management, Communication and Information) in almost all kind of institutions and enterprises. A short overview about the general role of evaluation and former findings leads to the depiction of the two case study regions, from where the empirical results have been gathered. The specific concept of the integrated particpatory sustainability managementsystem (IPSUSMAN) is then introduced. Secondly an advanced perspective on process of evaluation is introduced. It can be shown that the success of a management system is dependent on different influencing factors. From this it follows that a multi-perspective has to be used. A first outline of such an approach is given, the sub-methods are sketched and the complementary role of direct and indirect evidence in process evaluation is described. A small and therefore exemplary insight into some key findings from different surveys is illustrated. It can be shown that the acceptance of the Sustainability Balanced Scorecard (SBSC) is high amongst employees and when participation is encouraged it leads to a satisfying appraisal of the implementation process. With regard to sustainability reporting, it becomes evident that basic assuring technologies (e.g. certification) used in sustainability reports meet, at least partially, the expectations of readers that belong to different stakeholder groups. Strategic goals, based on participatory processes, reach a positive and mostly stable rating in the three pillars of sustainability (economic, ecological and social). Regional differences are of a lesser importance. In both case studies we find similar messages from indirect evidence (qualitative findings). The paper ends with a positive statement on the feasibility of the IPSUSMAN but also with a cautionary comment on the relative effort of time and money it takes to run such sophisticated systems.