As a wide variety of interaction devices, modalities has to be supported by user interface developers, model-based user interface development gets increasing attention. Especially if context- and user-awareness comes into play, handcrafting a user interface is rendered almost impossible. In modelbased user interface development, usually several models are applied to describe different aspects of the user interface or to provide a varying level of detail. The relations between the models representing those levels of ions are established through transformations, a concept which is also applied in software engineering with the Model Driven Architecture (MDA). In this paper we will review several transformation systems and discuss their applicability for model-based user interface development.