In 2011, the EPFL Library conducted real-life parallel tests of four major providers of so-called "resource discovery services": Summon, EBSCO Discovery Service, Primo Central Total Care and Worldcat Local. The aim was to replace the Online Public Access Catalog (OPAC) currently in use at the EPFL Library and shared with all libraries of the NEBIS network. The Swiss meta-catalog Swissbib and Google Scholar were used as reference. The above products were tested against the following basic requirements: simultaneous search through multiple data sources, global search index instead of federated searches and hosted instead of local installation. Choosing the best tool depends greatly on the local context. This report aims to expose the strengths and weaknesses of the current offering in discovery tools, and what they would mean for the EPFL Library. It is therefore not meant as a definitive judgment on the merits of each tool but rather as an illustration of the issues raised while adapting such tools to an institution such as EPFL.