This study explores the investment in Industrial Internet of Things (IIoT) systems among small and medium-sized enterprises (SMEs) in the German manufacturing sector. Despite the growing adoption of IIoT and its potential to enhance operational efficiency, there is a lack of empirical research on its implementation and impact. This research aims to fill this gap by conducting a comparative case study of six mid-sized German manufacturing companies. Key findings reveal a consensus on the potential of IIoT systems to improve efficiency through time savings, automation, proactive maintenance, and optimization of administrative processes. The study also uncovers diverse implementation strategies, with most companies favoring a comprehensive “big bang” approach over incremental adoption. Decision-making processes for IIoT investments vary, often involving a balance between quantitative and qualitative criteria, with the managing director playing a central role, especially in larger investments. The findings underscore the strategic importance of IIoT investments and highlight the need for a flexible approach to decision-making and performance evaluation. This research contributes to a deeper understanding of IIoT implementation in SMEs and provides a foundation for future studies on optimizing IIoT investments.