Performing experiments that involve a large amount of resources or a complex configuration, proves to be a hard task. We present Expo, which is a tool for conducting experiments on distributed platforms. First, the tool is described along with the concepts of resource and task sets, which abstracts away some of the complexity in the manage of resources and software execution. Next, the tool is compared with other similar solutions based on some qualitative criteria, scalability and expressiveness tests as well as the feedback coming from using dedicated testbeds. The report finishes with the evaluation of Expo scalability and some uses cases in Grid'5000 and PlanetLab. Our experience showed that Expo is a promising tool to help the user with two primary concerns: how to perform a large scale experiment efficiently and easily, together with its reproducilibity
