Optimized guidelines for the design of power converters are crucial to achieve the expected goals in terms of performance, efficiency, power density, etc. Therefore, they are the basis for industrial success or failure. Resonant converters based on Dual Active Bridges (DABs) are particularly sensitive to the design process due to their inherently nonlinear behaviour; thus, they are in the spotlight for research and development at present. Plenty of design methodologies can be found in the literature but each of them is specific to the perspective of the authors, the performed analysis, the assumptions made, and the design objectives. It is critical to understand the Key Performance Indicators (KPIs) and design methodologies of a resonant DAB converter. There is a significant lack of articles that concisely and clearly summarize this. Different design methodologies are analyzed and compared with respect to the most important KPIs, and the most relevant demos and experiences are pointed out so that designers can select the best choice for their assignment. These results will help designers understand the design methodologies and carefully choose one based on the application, analysis, and design objectives.