The lectures have a ton of gems in them, but I have a hard time following the lectures as a beginner/intermediate practitioner, as around 1-5 percent is relevant for me.
I don't particularly like the fastai library as it feels like an obstacle between me and the underlying pytorch library. After trying to use fastai for some time, I started looking directly at pytorch and found that all the abstractions and features I liked with fastai were actually from pytorch.
That said, it's a great resource and if you're doing cookiecutter stuff it seems pretty nice. Also, students of fastai have done some pretty amazing things. I like how Jeremy emphasizes the top-down view, but it's very hard for me to submit to it. I can't shake the need to understand the underlying ideas and build stuff bottom-up, even though I see my progress suffers from it.