Social signal processing and virtual social interaction technologies have allowed the creation of social skills training applications, and initial studies have shown that such solutions can lead to positive training outcomes and could complement traditional teaching methods by providing cheap, accessible, safe tools for training social skills. However, these studies evaluated social skills training systems as a whole and it is unclear to what extent which components contributed to positive outcomes. In this paper, we describe an experimental study where we compared the relative efficacy of real-time interactive feedback and after-action feedback in the context of a public speaking training application. We observed that both components provide benefits to the overall training: the real-time interactive feedback made the experience more immersive and improved participants’ motivation in using the system, while the after-action feedback led to positive training outcomes when it contained personalized feedback elements. Taken in combination, these results confirm that both social signal processing technologies and virtual social interactions are both contributing to social skills training systems’ efficiency. Additionally, we observed that several individual factors, here the subjects’ initial level of public speaking anxiety, personality and tendency to immersion significantly influenced the training experience. This finding suggests that social skills training systems could benefit from being tailored to participants’ particular individual circumstances.