Schema mappings are fundamental building blocks in many information integration applications. Designing mappings is a timeconsuming process and for that reason many mapping systems have been developed to assist in the task of designing mappings. However, to the best of our knowledge, a benchmark for comparing and evaluating these systems has not yet been developed. We demonstrate STBenchmark, a benchmark that we have developed for evaluating mapping systems. Our demonstration will showcase the different aspects of mapping systems that STBenchmark evaluates, highlight the results of our comparison and evaluation of four mapping systems, as well as make a case for the need for a standard specification input mechanism to mapping systems in order to make progress towards the development of a uniform testbed or repository for schema mappings and data exchange tasks.