I definitely think it's better to read the book before watching the movie, especially the end of the book where the author explains what they (Maren, Lee, Sully, etc) are. I, personally loved the movie. It's so well done, and the cinematography is just amazing. Luca is brilliant, and the actors really brought Camille DeAngelis's work to life. I loved how detailed the horror/cannibalism elements were, and as weird as it might sound, this movie was a huge comfort to me. 100% recommend it!