Overall, this evaluation can be summed up like this: the concepts may be intriguing, but the storytelling is poor.
Would virtual reality work the way the author thinks it would?
While some people thought Schroeder's world building seemed interesting at first while the story centered on Teven Coronal, later in the book both the world building and the plot faltered. A few people gave the author credit for developing something rarely seen in SF, countless overlapping virtual realities with no "baseline reality", but others thought his descriptive powers were not up to par to this undoubtedly difficult task. One reader found the portrayal of virtual reality unconvincing: "The fundamental idea of multiple overlapping realities was such a cool idea, and yet he didn't entirely convince me that in his version of it it makes sense. There were so many questions about, what if there are physical obstacles from one reality imposing on another reality? And he kind of danced it around it a little bit about having software impose a compatible obstacle, or even suppress your awareness of the motions you made to walk around something, to make you feel that you're walking in a straight line, but he didn't quite convince me that it would work." At the same time he acknowledged that Karl Schroeder's attempt at depicting virtual reality was more ambitious than what most writers had done before.
Can too much reality-editing technology ruin a science fiction story?
Another reader was even less impressed. "I see mundaneness everywhere, and I don't think that's what he intends to describe," he said. He thought Schroeder could have built a much more impressive world given the technology available in this world. He quotes examples of technological blunders in the book that one does not expect from a writer of hard science fiction. Case in point: "[In the scene where they are travelling in space], they spin up to get half the g, and they are looking out with the telescope. What's wrong with that scene?" he asks. "They are spinning like hell! You need to spin really fast to create an artificial gravity of half g." If they tried to look out the window while spinning this fast, they would see nothing but a blur. Another group member countered that the telescope output was edited by the virtual reality software (called inscape in the book) to eliminate the blur, making it look as if there was no spinning.
So there's an interesting dilemma. Too much reality-editing technology can, at best, make the world described in a science fiction book look mundane, and at worst, mistakenly imply that the author doesn't understand science. There's a fine line between giving your characters full control over the reality they experience, and shielding them from experiencing anything unusual, which would defeat the point of writing science fiction in the first place. The group for the large part seemed to think that Schroeder does not walk this line very well. This was the main source of dissatisfaction for some of the readers. When the virtual reality started to fall apart, it promised some interesting developments as the characters are forced to deal with the raw, unedited world. But it didn't happen. A reader said: "It starts out, we are in the virtual reality world and something weird starts happening. From the title "Lady of Mazes" I expected a series of puzzles to unravel. As the virtual reality world kind of fell apart, I thought, this was going to get interesting. And when they say, we're going to reinvent science, I thought, cool! And reinventing science is, you are in a house and put a sign on the house of your destination, and throw yourself of the cliff, that's reinvention of science?"
He was talking about a scene that exemplifies the low-tech feel of the book, unexpected for a hard science fiction novel. The three main characters launch themselves into space by getting into a house and throwing that house off of a cliff -- or, to be exact, off the edge of their world. The destination sign is the way to communicate their destination to the forces / mechanisms that run the set of artificial habitats floating in space, known as coronals. The forces read the sign and deliver the house to the right habitat. The same reader goes on to say: "They go around the ringworld, and they find nothing? OK, so let's go to Jupiter. And there's more virtual reality people! I wanted not the virtual reality people, I wanted the real world stuff! I was hoping I'll find people dealing with real science, real world stuff, but no."
Personally I have to admit I liked the scene with the house falling off the edge of the world. Given that the three main characters had zero familiarity with spaceflight, I thought it was both a brilliant and quirky way to escape the confines of their world. At that point this novel got me hooked. It was temporary, though. The book went downhill from there.
The group was also unanimous in the opinion that the middle third of the book was poorly plotted; the narrative meandered and snarled. A reader said: "When [the characters] got to the Archipelago, it's like [the author] didn't know what to do. It kind of really slowed down, bogged down the whole thing".
Somebody was also disappointed that the psychological suspense in the book does not get satisfactorily resolved. A reader said: "there was this psychological suspense about why [Livia] reacted in certain ways, and what really happened back at the time of the accident. That scene should have been extremely intense, it should have been the point of the book, and it just didn't have the payoff it should have had."
I found characters motivations and their personal philosophies unconvincing
I wasn't convinced by the characters' personal motivations, or even by the philosophical conclusions they arrive at in the course of the novel. First, there is this intriguing notion of "tech locks", which was one of the concepts that made me want to like this book, even though I was eventually unable to. The idea is that when we are choosing technologies we use, we are choosing our values. "Tech locks" are technological limitations, restrictions that prevent the society from using certain technologies. Those restrictions are self-imposed by the society. One of the main characters thinks society should not censor itself by dismissing entire classes of technologies; he thinks humans can't live authentic lives without complete technological freedom. Then the world they live in comes under attack from a superhuman power that wants to destroy the tech locks. The book does not make it clear why it wanted that -- maybe just for the sake of an experiment? Then it turns out there are not just one, but two superhuman / transcendent entities warring against one another, even though both of them want to destroy the tech locks. The main characters, who started out on a mission together to find help for their homeworld, split up and align themselves with one power or the other for no good reasons. Their choices don't seem to flow from deep inside their personalities. Once they started making arbitrary choices, I stopped caring about what was happening to them.
The book delivers a conservative message
The central message of the book -- the one behind which I think I recognized the author speaking through a minor character's lips -- was even less convincing. If there are no tech locks, the message says -- if you are not restricted by a system of technologies / values -- then your life becomes meaningless, because you become "walpaper". You lose your uniqueness. Your life becomes identical to billions of other lifes. You are bound to do the same things, speak the same words as billions of other people. I did not see how the author arrived at this conclusion. If anything, freedom to choose any technologies one wants should enable each of us to build richer lives. I guess I don't agree with the equation "tech locks = values". Lack of a society-wide veto on certain technologies is not equal to preservation of values. A person's values can, and should, dictate technologies they use on a case-by-case basis. I don't see how it can be useful to exclude entire classes of technologies a priori. So I guess I found the message of the book to be unexpectedly conservative for an author who has a reputation of being on a cutting edge of science fiction.
What did the group like about "Lady of the Mazes"?..
... if anything? The readers gave Karl Schroeder points for trying. Few writers try to create a virtual reality world as complex as this one, or an interesting mix of human and posthuman societies. It was also acknowledged that Schroeder's writing has improved since "Ventus". This was followed by a meta-discussion of why "Lady of the Mazes" got all the rave reviews from a bunch of science fiction luminaries such as Charles Stross and Vernor Vinge. Those reviews were what made some hard SF fans in the group want to read this book in the first place, only to be disappointed. It was suggested that since these authors explore similar topics, such as singularity and post-humanism, and they all write works that are heavy on ideas but a bit weak on characterization, it is conceivable that they overlooked mediocre storytelling in favor of the ideas.