Many organizations using Free/Open Source Software (FlOSS) are dealing with the major problem of selecting the most appropriate software product corresponding to their needs. Most of theses companies are currently selecting FlOSS projects using adhoc techniques. However, in the last couple of years, two methodologies for assessing FlOSS project have emerge, namely QSOS and OpenBRR. The objective of this work is, through a detailed and rigorous assessment methodology comparison, to allow companies to have a better understanding of these two assessment methodologies content and limitation. This work compares both methodologies on several aspects, among others, their overall approaches, their scoring procedures and their evaluation criteria.