Pedestrians–cyclists shared spaces, sidewalks and streets are now a commonly implemented urban design solution in many cities, due to the willingness to promote sustainable mobility and the non-availability of public space. The proper design and management of these infrastructures requires an accurate evaluation of their performance. The most dominant evaluation metric is the level of service (LOS) and various methodologies have been proposed in the literature for its assessment in infrastructures that are being used by pedestrians, cyclists or by both of these two types of users. The present paper gathers and presents various methodologies, and it applies some of them on two pedestrians-cyclists shared spaces in a medium-sized city in Greece. The outcomes of the methodologies are being compared both among themselves and in relation to the opinions of the users, who participated in a questionnaire survey. The review of the literature, along with the application of some of the methodologies, leads to a fruitful discussion, which sets the groundwork for future research in the field of LOS and it also assists practitioners in selecting the appropriate methodologies for the assessment of pedestrian–cyclists shared spaces.