With the Model Driven Architecture (MDA), the role of model composition has become very important. One challenge in model composition is specifically to merge models expressed in the Unified Model Language (UML) and its extensions. However, to put model composition in practice it is necessary to perform an essential task: model comparison. In this paper, we present a model comparison technique that aims to insert flexibility into the equivalence definition process between input models of a model composition mechanism. Such flexibility is achieved by match strategy. Hence input models are merged if they are considered equivalent according to a specific match strategy. Such strategy is implemented by a match operator that makes use of match rules, synonym dictionary and typographic similarity. Moreover, some challenges are specified and a guidance defines the activities that should be performed throughout the model comparison process.