The downside is that the book is extremely unbalanced, especially so when the author begins discussing the significant comforters that she interviewed for the primary material of the novel. The book slams to a halt to talk about their backgrounds, then quickly list off their comforting suggestions at the end of their profile in bullet points. If it had been integrated in a bit better, this review could easily have had another star added to it.
The last fourth of the book is even worse, as it just amounts to the author listing off music, movies, books, and the like that the author feels is comforting, but without any real explanation about why. Given that this section is aimed at helping people who need comfort in their lives, trigger or content warnings probably should have been listed next to some of the darker titles. Unless you're already familiar with the titles listed, it's really not that much of a help. It's even more jarring since the recommended reading and website section has mini-descriptions for every title.
At the end of the day? Even with these problems, I'd happily recommend it to anyone that wants to improve themselves but doesn't know where to begin, or doesn't like heavy material. It's not a bad book, it's just not perfect.