This work aims at developing appropriate Mixed Interaction Systems (MIS) for navigating 3D environments in a science centre context. Due to the wide range and multi-disciplinary design aspects to consider in this context and the lack of expertise in terms of MIS and public context evaluation, designing and evaluating MIS is a complex task. Based on an integrated development process, which combines a design model and a user-testing, this paper presents the outcomes of the comparison of two MIS in terms of performance and satisfaction.