Background: Case studies and experiments are research methods frequently applied in empirical software engineering. Experiments are well-understood and their value as an empirical method is recognized. On the other hand, there seem to be different opinions on what constitutes a case study, and about the value of case studies as a thorough research method. Aim: We aim at exploring the attitudes of software engineering researchers on case studies and experiments. Furthermore, we investigate how the perceptions of researchers vary along their views on what constitutes a case study. Method: We performed an exploratory survey involving 26 software engineering researchers. We collected data using a paper-based questionnaire. Results: We found that participants slightly prefer experiments over case studies. Moreover, participants believe there is more useful literature on experiments, than on case studies. By analyzing two different views on the nature of case studies, we found differences in the perceived validity of case studies. Conclusions: The survey provided insights into the perceptions of researchers on case studies and experiments. Moreover, the results help reconcile different views on case studies.