This paper presents a comprehensive usability study conducted within the context of a Europe-wide project. The design of the evaluated e-learning platform is based on an innovative approach to the education of young Europeans by integrating into the curricula of a Europe-wide network of 14 schools different state-of-the-art technologies in e-learning. The evaluation methodology brings together end-user assessments and expert inspections, thus providing a detailed students', teachers' and experts' feedback. User testing integrates six empirical methods into a laboratory-based test. Usability inspection ascertains usability problems by means of recognized heuristics and enables an "educational evaluation" of the platform by means of three sets of criteria. The paper aims to present the effectiveness of the engaged evaluation methods as applied to e-learning platforms. It offers implications from the empirical findings of the user-based methods together with a quantitative and qualitative analysis of the employed inspection methods. Special attention is given to the aspect of educational evaluation. The conducted critical usability examination of a large-scale e-learning system across several countries in Europe revealed which of the chosen assessment methods should be combined to provide constructive and valuable improvement suggestions. A more significant contribution of this research is that the used evaluation approach proved successful, providing some general findings and know-how from the experience and could be reused by other researches because of its thorough structure. As there are relatively few existing accounts of usability assessment in the e-learning context, this paper adds to the body of knowledge. (Contains 15 figures.)