The digital revolution towards the industry standard 4.0 offers many ways to improve established methods and processes. In this paper, we report on the lessons learned about the pros and cons of Augmented-Reality-based operator training using the Microsoft HoloLens as compared to small and big screen tactile devices. Together with our industrial partner, we have chosen an encapsulation assembly task as use case. We have enriched the original training material with digital twins of the workplace, animations, videos, and contemporary forms of interaction, all of which made available in an optimised fashion on three different support technologies. Feedback from our testers, and those in charge of designing training courses, is suggesting that notably the HoloLens version of our prototype has the potential not only to replace current training methods, but to go beyond them up to the point where even novices can pass the training autonomously. It thus seems promising to integrate Augmented Reality into training programmes and so to complete the digital chain within the industry life management.