I will often forgive a middling book if it has a few great ideas. I felt that the tech in this book was so loosely defined that I had trouble understanding what was within the realm of possibility. Felt like the story might be better set up as a punchy exciting animation rather than within the written word. I enjoyed visualizing the scenes, but when I think about the plot (tangled beyond my keen) or characters (whose motivations are still to be revealed) I was a little less impressed.
It might have been 4, but I also read this book over a period of around a month. I think, if you are going to read this, it is better to finish it quickly over a few days. It is that kind of novel.