Although immersive virtual environments have been used for years for training and learning purposes (e.g., flight and surgery simulators), the effects of using VR devices on simulation sessions are yet to be understood. In this work, we explore the effects of different VR devices on virtual environments developed for training, focusing on perception and knowledge gain aspects. We performed two user studies to investigate the influence of these devices on users' workload, motion sickness, and performance in the domain of work safety training. The first experiment includes 61 participants and seeks to understand whether and how VR displays providing different fields of view affects the users' ability to search for risks in an office-like virtual environment (i.e. focus on user perception). Subsequently, we conducted a second experiment involving 46 subjects, where we assess whether and how interaction techniques providing different degreesof-freedom influence users' ability to learn procedural tasks (i.e. focus on knowledge gain). From our results, we learned that users' knowledge on the simulation's topic (i.e. work safety) and gaming experience play an important role in VR simulations, and that cybersickness symptoms such as disorientation are likely caused by unawareness of one's surroundings instead of VR content.