Hello,
It really depends on you and on which part of your preparation you want to reinforce.
I have heard about that source and I have worked with a couple of guys that used it: it's an interesting material if you have experienced difficulties in structuring your cases.
On the other hand. as you know, structuring a case in the right way is fundamental but it's just the first step for a good interview. If you want to focus more on your soft skills or on handling the information they provide you, it's better to focus on "live cases".
Hope it helps,
Luca
Thank you Luca for your comment! I am having some difficulties to structure the cases very well. However the softskills are equally important if not even more important! Could you share some of your experiences with me about how you practise that soft skills or handing received information? Thank you so much!
I think that the only effective way is to practice with live cases and other people. There is a huge difference between studying recommendation and really using them in a real interview