I finished reading this series a few days ago and really liked it. It gets four stars out of five from me. Some mild to moderate spoilers below; skip to the last two paragraphs if you don't want to deal with them.
I originally found the series on TVTropes and was drawn in by the awesome titles--I still maintain they are the best novel titles I have seen. The series is set in what appears to be the 24th or 25th century, in a post-Singularity world where Sobornost mind-upload collectives roam the Solar System in planet-sized diamond spaceships; Zoku colonies descended from gaming guilds live in the outer Solar System, bound to each other by quantum entanglement; and pockets of baseline humans still remain in places as diverse as Mars and the Oort Cloud. It is in this world where the titular posthuman thief of minds and thoughts, Jean le Flambeur, is broken from the Dilemma Prison--a strange place where prisoners are forced to endlessly play the Prisoner's Dilemma with each other--by Oortian warrior Mieli, who serves a Sobornost goddess, Josephine Pellegrini. They have a mission for him, but first he must travel to the Oubliette, the walking city of Mars, a human city swathed in endless layers of encryption, a city where privacy is the highest value and people communicate with memories, to recover his memories.
The second book, The Fractal Prince sees Jean le Flambeur, Mieli, and her sentient spaceship Perhonen journey to Earth to carry out their mission: to find an ancient mind-copy--a gogol--of a Sobornost Founder. To this end, Jean travels to Sirr, only post-Collapse city on Earth. Sirr is an odd city, made from the remains of a fallen space station and surrounded by a desert of gray goo, where humans coexist with disembodied mind-uploads called jinn and maintain an uneasy alliance with the Sobornost, who cannot venture into the desert and must thus rely on humans to harvest the gogols the Sobornost need for the Great Common Task. It is here where Jean works with the help of Sirr woman Tawaddud Gomelez to find the gogol. But le Flambeur and his associates are not the only ones who seek the Founder gogol: the Sobornost seek it too, and they are coming.
In the third and final book, The Causal Angel, the fate of the Solar System hangs in balance, as the Sobornost and the Zoku colonies of Saturn prepare for war. Jean le Flambeur has paid his debt to Mieli and the two have parted ways. Mieli has gone to Saturn to join the Zoku in the fight against the imminent Sobornost invasion. Meanwhile, Jean and the childhood gogol of Sobornost Founder Matjek Chen have teamed up for one last great heist, one that will shape the fate of human civilization and the universe itself.
The best thing about these books is that they in no way project the present onto the future. Not in the slightest. It's really refreshing, especially after seeing so much drivel that reads like the 2010s--or even the 1990s--with a thin veneer of shiny shit plastered on. Or else, fails at basic science. (The science in these books are too advanced to criticize intelligently!) I'm not saying that you can't have good science fiction where things aren't too far removed from today, but in my opinion anything set beyond about 2100 has to be at least a little bit weird to be believable. And the Jean le Flambeur series is very, very weird, in all parts of the Solar System, be it the quantum hyper-technology of the Zoku, the raw power and endless mind-copying of the Sobornost, or the peculiar human enclaves on Mars and Earth. And secondly, this is a post-Singularity world where death and scarcity are almost nonexistent...but all is not well, everything is not some kind of shining utopia. It tickles me pink to think what certain people on this forum would make of that. It sort of illustrates my belief that while technological advances will solve problems, they will create newer, more complex problems in their wake: the past thousand years are a testament to that fact. And I find Jean le Flambeur a fascinating, if bewildering and enigmatic character with a mysterious pass.
Now for the flaws. The most obvious one you'll notice is that nothing makes any sense. You're dropped in a hyper-futuristic world and have to figure out stuff for yourself--both worldbuilding and technology. I get that this is subjective--for some it's the greatest appeal. But for me it's the biggest flaw. I like worldbuilding. In my own writing, I like to liberally sprinkle details about the world. But here there is little of that, very little. It makes the plot and action very hard to follow (I still don't know who the hell are the Aun or what they do or how they came to be!) and I found myself just sort of nodding along with it in a lot of places. The Fractal Prince was especially flawed in this regard, I dunno, Sirr was just bizarre. Too many terms thrown out and never explained. I also don't really like it when there is a first person narrator who isn't always there, forcing the book to occasionally revert to third person. If you don't want to have your narrator always be there, use third person dammit! But that is a minor flaw, and I eventually got used to it.
(image sources: amazon.com)