I loved this book, but it's not for the faint hearted. Rajaniemi eschews any exposition, which I like because it always feels jarring to me when sci-fi characters stop to explain to each other how something they use every day works.
I think that works: on the surface the dense sci-fi terms read like magic, especially for the humans still on Earth, but then you read up on it and gain an additional layer to the story. For instance to the humans there's a kind of spirit world, but to the post-humans it's a broken augmented reality environment full of damaged copies of dead human minds.
It's also a worst case scenario for a singularity gone very wrong - instead of a digital upload utopia a few minds (founders) retain all the control, with most of the uploaded reduced to Gogols (an enslaved copy of a mind). I like that slightly dark, cynical view.
The story is told with many nested stories, and those are themselves part of the plot. That adds to the slightly mystical tone to the book, but also adds to the confusion. This is definitely a book I'll read again, probably after re-reading The Quantum Thief and before Rajaniemi publishes the next one.