In the literature, it is often assumed that traditional, control-oriented HRM systems are increasingly being replaced by commitment-based HRM systems because the latter generally result in higher firm performance. However, an HRM system's effectiveness may depend on an organisation's external and internal context, and neither control nor commitment HR systems are without disadvantages. Thus, the empirical validity of this claim is not clear ex ante. This paper analyses the empirical diffusion and determinants of control and commitment HRM systems in Germany as well as their impact on HRM outcomes and firm performance. The findings indicate that between the two extreme forms of high-control and high-commitment HRM systems, there are two hybrid forms (long-term-oriented control system and regulated commitment system) that combine elements of both ‘pure’ systems. Commitment HRM systems outperform the high-control HRM system concerning many HRM outcomes and firm performance measures. However, in direct comparison, the high and the regulated commitment HRM systems do not show substantially different outcomes, indicating that there is no one best way.