This chapter presents an analysis of convergence and divergence of the various methodologies. It reviews several different classifications previously proposed in the literature, and then attempts to determine relevant criteria for grouping and classifying the methods. Finally, these methods are effectively classified and compared on the basis of the criteria established through this analysis. The analysis shows that the majority of the methodologies reviewed pertain to companies whose services are strikingly marketing oriented, and that therefore those based on demand driver analysis or brand strength are the most prevalent. Of the 39 models studied, 14 specifically represent the brand's useful life and expected growth. The analysis presented here manifests the way in which providers typically present these variables in their commercial literature, and by no means dictates the manner in which the said variables are to be treated in subsequent applications of the models in which they appear.