The SusProNet project aimed to analyse the state of the practice and knowledge on product-services. Product-services are a specific type of value proposition that a business offers to its clients. The product-service systems (PSS)may be complicated and require a lot of investment. Usually, totally new competences need to be developed or marshalled. The opportunities and threats of PSS development can also be analysed by type of PSS. The chapter shows an intriguing contradiction with regard to the environmental and economic potential of PSS. From the analysis of PSS best practice and state of the art in SusProNet, the following guidance for further activities to support PSS development in practice can be derived. The methodological toolbox for PSS development is fairly complete. One of the more laudable attempts to at least investigate this 'reality gap' comes from Thierry Kazazian, who thought out sustainable PSS business models with regard to food and water provision.