Software as a Service (SaaS) applications provide resources that need to be customized in order to satisfy various tenants’ requirements. In a previous paper, we proposed a SaaS application customization approach to provide a tenant administrator with a suitable way for customizing SaaS applications and validating each customization during run time. In this paper, we provide an evaluation of a previous approach by giving a detailed com- parison with other approaches, and by showing the performance of our approach with and without applying aspects. The evaluation shows the ability of our approach to deal with all variability and constraint dependencies. Moreover, the comparison with other researches demonstrates that the more SaaS applications have the ability to be customized, validated, and adapted to the changes during run time, the more they become upgradable, maintainable, adaptable, understandable, and secure.