The introduction of agile methodologies such as Scrum considerably changes the working habits of developers. To ensure their successful dissemination, it is therefore particularly important that developers assimilate and remain committed to agile principles. In this paper, we examine the long-term acceptance of Scrum and present the results of a study conducted at a world-wide leading insurance company that began transitioning to Scrum in 2007. Taking the Diffusion of Innovations theory as a lens for analysis, we identify several acceptance factors of Scrum and hypothesize how they are perceived in comparison to traditional methodologies. We evaluate our hypotheses using a multi-method research approach that combines analyses of quantitative and qualitative field data. The results suggest that several factors of Scrum are perceived as relative advantages or as more compatible to the way developers prefer to work. Factors that characterize the complexity of Scrum are identified as potential barriers to acceptance, however.