An entertaining space-opera, but I was hoping for something deeper or more grandiose in scale, like a Baxter or Stross novel. 
 The most intriguing parts of the story(view spoiler)[--dreams that the main character had that hinted at something outside the universe, and a recurring theme of his name having been stolen-- (hide spoiler)]went unresolved and unexplained at the end. Worse, (view spoiler)[most of the protagonists end up dead at the end, so (hide spoiler)] there's little chance that those specific things will be explained. 
 The universe features sentient machines who wish to be treated as equals; the main character and most other characters almost always treat them as non-persons, calling them "machine," etc. I would have liked to see these tensions and attitudes around emerging AI sentience explored more instead of treated as matter-of-course inferior. 
 Many more aspects of the Culture universe went mentioned but unexplored, so I'm hopeful that these were prompts for elaboration in later books. 
 This was the author's first Science Fiction book, and the others in the series are more highly rated both on this site and by friends, so I'm hopeful that it gets better from here and those things hinted at are explored further in later books.