Data distributions systems with guaranteed Quality of Service (QoS) levels, such as the data-centric Data Distribution Service (DDS) standard specification, have gained more and more success in the last decade. These systems represent suitable solutions for effective and high-performance data communication for challenging application scenarios with real-time requirements, such as air traffic management, industrial automation, smart grids, and, more recently, financial applications. Notwithstanding the last decade has witnessed the diffusion and consolidation of some major implementations, only a very few, in some sense obsolete, performance analysis studies are available in the literature. To fill that gap and to facilitate future IT decision processes, we propose a thorough analysis of the DDS implementations proposed by the two main stakeholders in the DDS market, namely, PrismTech and Real-Time Innovations (RTI). The reported experimental results point out the pros and cons of both solutions in terms of data delivery performance, also by precisely evaluating bottlenecks and overhead, for instance in terms of CPU and memory resource usage.