I was initially attracted to Devotion of Suspect X because it is part of Higashino's Galileo series. I watched the Galileo drama (Japanese TV Series) and loved it. I don't think the drama contained this book. Devotion of Suspect X is the first of Keigo Higashino's books in this series to be translated into English.
I liked the book. A large part of the book is cryptic. The characters speak in riddles and puzzles that only make sense in the end. The language however, is to the point. Unlike a lot of English mystery novels that focus on the procedure of solving mysteries, this one focuses solely on the story. That saves a lot of boredom and keeps you turning pages. The translation was well done. The story flows in a coherent narrative. My only complaint was that the character of Manabu Yukawa in the novel is not as charismatic as the series. Yukawa's sidekick also doesn't make an appearance in this one.
Overall, a fast paced, well plotted mystery. It's the kind of book you'd read on a cold evening or on the flight.