Beyond 5G and 6G systems provide significant advances in network architectural design and deployment with the ever-increasing connected devices. In order to address the tremendous growth of cellular traffic, both hard- and software are facing increased scalability and flexibility requirements. Therefore, a comparative study on open-source 5G core network implementations is conducted that includes qualitative as well as quantitative requirements. While the qualitative comparison is based on licensing, programming language, deployment possibilities, and relevance, the qualitative metrics are resource utilization and the Round Trip Time experienced by end-user devices. In order to evaluate these metrics, each of the open-source projects is deployed as service based architecture in a virtual machine/container-based infrastructure. The results indicate implementation benefits and the trade-off between load consumption and latency evaluation.