Fastbook or course-v4?

According to the instructions here, we are supposed to click on fastbook folder but the corresponding image shows course-v4 folder was clicked. Which folder should we use for learning?

the notebooks in course-v4 are the same as the those in fastbook, except that those in course-v4 just have the code and the text and pictures of the book are in fastbook nbs.

I think the fastbook notebooks are better for reading/referencing by themselves, but the course-v4 notebooks are better when following along with the tutorials (less verbose).