The goal of this research is to examine the impact of media formats used in web-based courses on the way students perceive these courses and on their performance in the courses (in terms of grades). Factors influencing the evaluation of web-based courses by the students are analyzed, based on courses of an online distance-learning graduate program. In particular, we studied conventional hypertext-based courses, video-based courses and audio-based courses, seeking to find out whether the media format has an effect on how students assess courses and how good or bad their grades are. Statistical analyses were performed to answer several research questions related to the topic and to properly evaluate the factors influencing student evaluation.