Digital preservation has turned into a pressing challenge for institutions having the obligation to preserve digital objects over years. A range of tools exist today to support the variety of preservation strategies such as migration or emulation. Heterogeneous content, complex preservation requirements and goals, and untested tools make the selection of a preservation strategy very difficult. The Austrian National Library will have to preserve electronic theses and dissertations provided as PDF files and are thus investigating potential preservation solutions. The DELOS Digital Preservation Testbed is used to evaluate various alternatives with respect to specific requirements. It provides an approach to make informed and accountable decisions on which solution to implement in order to preserve digital objects for a given purpose. We analyse the performance of various preservation strategies with respect to the specified requirements for the preservation of master theses and present the results.