The first novella in the book, "Diamond Dogs," has some very interesting secondary characters and an intriguing setting, but overall, there is not enough to sustain interest - depending on if you like mathematical, geometrical puzzles that you cannot see (i.e. there are no drawings or pictures accompanying the text), you may find yourself skimming paragraphs and pages.
The second novella, "Turquoise Days," is significantly better and I certainly thought the setting and the characters may have been one of Mr. Reynolds original storylines in his novels, but might have been edited out in favor of another. As such, the characters are more developed, the story much more engaging, and the pacing well done.
If you are an Alastair Reynolds fan, get this book; if you are new to his writing, I'd skip this in favor of PUSHING ICE.