It's a fine and entertaining book, with an exciting detective plot. I can say it was an easy read without any flowery prose (which is not necessarily a compliment...). I've never played any of the Mass Effect games, but this is a book which introduces quite well the ambiance, all the political scenario and alien cultural diversity. I felt that you don't have to know the Mass Effect lore previously when reading, which is great (these books inspired or based in games tend to be dull sometimes, especially when the author thinks the reader knows all the lore, etc).

Despite being characterized as a sci fi book, it lacks the substance or the base of any good science fiction book. Since it's just a detective story, the reader doesn't have to think, to reflect on Humanity dealing with the technology, the future, etc. It's a book which lacks several interesting scifi concepts though, such as the Reapers/Geth plot, the discussion on Humanity versus machines, AI, etc. All these concepts are introduced in this book, but not discussed.