I liked this one a lot, but can't really put my finger on why that is. I'll try. There are a lot of badass women and girls involved, which is always great. As well as the setting of an institution where said girls learn from said women. I love these types of scenes where characters train and find their power, it's simply a lot of fun. While this book is pretty dark, it is less gore and brutality heavy than I thought it would be, which is also great, especially since it doesn't lose it's rather dark tone because of that. (Also, the German narrators voice is relatively warm, which sometimes clashes with the writing, but I liked it, because it made it easier for me to like the characters.)
Even though the magic system is pretty soft, I still enjoyed it a lot. Cool powers, interestingly told, thumbs up.

But I do think that this book would've been much harder to get through if I read it instead of listening to the audio book, because it is sooooo slow. There's barely plot, it feels like an entire book of exposition for the most part. Getting to know the characters (though I have to admit that I still mix up the nuns a bit), their training, watching them bond etc. ... I mean, it is entertaining, but if you're there for a lot of plot, you will be disappointed. A lot of scenes are not necessary to get the point across/tell the story. The little bit of plot that is in there is great though. But as said, if I read a physical copy it would've taken me forever and I honestly don't know if I'd liked it as much.