Software architecture change can have a major impact on product and project quality. Software architecture evaluation systematically investigates architecture variants with respect to their quality attributes, e.g., modifiability and maintainability of a software system. Scenarios and system properties are key elements to focus architecture evaluation on most likely future changes in the software architecture. Scenario elicitation processes typically include individual scenario brainstorming and a team meeting of all relevant stakeholders to create an aligned list of important scenarios. A major research question is which meeting style, face-to-face meetings, nominal (i.e., non-communicating) teams, or distributed tool-supported team meetings are most effective. In this paper we report on a controlled experiment investigating the meeting style of scenario brainstorming processes. Major result is that face-to-face meetings outperformed in the experiment tool-supported meetings in finding more important scenarios.