In Software Product Line Engineering (SPLE), the ability of a software artifact to be used in different contexts is very essential for productivity. In order to manage and support this ability, different variability modeling methods have been proposed. An important group of such methods are based on UML. These methods typically introduce profiles for specifying mandatory and optional elements, identifying dependencies between elements, and modeling variation points and possible variants. However, the assessment of these methods still lacks. In this work, we have done a first step towards evaluating the comprehension and utilization of variability issues in UML-based models by suggesting a comparison framework which refers to different aspects of variability specification. Based on this framework, we chose a specific UML-based method - ADOM - and examined how advanced information systems students understood and utilized a model specified using this method. The results showed that the different means for specifying variability were understood and utilized only to a limited extent and that variation points were the least comprehensible variability specification means.