In the last decade, several works proposed their own list of quality of context (QoC) criteria. This article relates a comparative study of these successive propositions. The result is that no consensus has been reached about the semantic and the comprehensiveness of QoC criteria. Facing this situation, the QoCIM meta-model offers a generic, computable and expressive solution to handle and to exploit any QoC criterion within distributed context managers and context-aware applications. For validation purposes, QoCIM is successfully applied to the modelling of a set of simple and composite QoC criteria.