Normally, the primary issue that I have with books is that they are well written but not interesting. "Perdido Street Station," on the other hand, was very interesting, but the writing got in the way of the story.
The book is about a scientist, an artist, and a vagabond and their endeavors in New Crobuzon, a melting-pot city that features many fantastical races (cactus people, bug people, frog people, bird people, etc). The setting includes a scientific understanding similar to the early 20th century (there is steam power and fairly sophisticated chemistry and biology, but the information revolution hasn't happened yet and neither has quantum physics). Magic exists alongside physics, and it manifests in a lot of ways, including "remaking," which means attaching animal or machine parts to humans (which the humans can then manipulate at a level more sophisticated than prosthetics).
All of that is really interesting. And the plot, which I won't reveal for the sake of spoilers, is also really interesting (though if you are familiar with my musings on books, you will know that a spoilable plot isn't something that i consider a virtue in a book). The presence of different races allows a moderately sophisticated critique of race relations. The city's early industrial status and corrupt government provide compelling reflections on poverty and government corruption. The vagabond's soul searching is poetic and makes me want more.
The biggest problem with the book is that it's confusing. There are two components of this: world dump and confusing words. The world dump was most severe in the first few chapters. I didn't think that I would read much longer than the first few because I had no idea what was going on at all with anything. The author has created a big and complicated world, and he seems compelled to include every minute detail about it. Thus, the first few chapters introduced dozens of facts about how magic worked and about the city and its denizens. The paragraph of this review that describes the setting -- imagine that spread out over 50 pages without much action, and you will understand why I almost quit the book. After that, the action started, and I understood most of the fantastic references, so the world dumping was less problematic. Throughout the book, though, the author continues to dump lots of slightly-relevant facts about the world, which makes the book fairly slow moving.
The confusing words make the book read like a postmodern treatise. The one redeeming factor is that, unlike postmodern literature, most of these words are actually in the dictionary, and since I'm reading the book on my phone, I can touch a word to pop up a definition. Despite that, the reading is arduous. I had to look up one or two words per page. Since there are a lot of fantasy words also, i don't always know whether a word is an English word that I don't know or a fantasy word that won't have a definition at all. I think that it's good to include some words that a reader might not know for the sake of expanding their vocabulary or for a particular artistic effect. However, when that is done well, the reader will often be able to infer the meaning of a word based on context. In "Perdido Street Station," it is difficult to infer meaning based on context. The confusing words are usually not artistic but slightly uncommon words, words that might be in the news or a poem or on the SATs. Rather, they are usually obscure words that are used infrequently enough that they no longer contain much of an artistic connotation in common usage. I wouldn't be surprised if the author took sentences that were easy to read and combed through a thesaurus to find more complicated words to substitute in.
But the confusing words aren't just obscure words. The author also takes normal words and tweaks them to make them seem weirder and more appropriate for a fantasy setting. For instance, instead of microscopes, there are femtoscopes ("femto" is a scientific prefix that means 10^-15. There are a thousand million million femtoseconds in one second. Micro can mean 10^-6, but in the case of a microscope, it just means small). If they actually had femtoscopes, then there would be no way that their science would be as rudimentary as it is. A femtoscope could see electrons. Instead of "chemicals," the book has "chymicals." Weird for the sake of being weird.
I'll stop ranting about the book being confusing.
Another issue I have is that the book is soft fantasy, meaning that the world doesn't seem to be internally consistent or completely thought out. In other words, there are a lot of obvious questions that a reader would ask about how the world works. In hard sci fi, the author might create faster than light travel or something else that defies physics, but the ramifications of that one change would be well thought out and consistent with one another. In hard fantasy, there might be magic, a system that describes how the world works that is separate from physics, but within that system, there aren't obvious holes.
"Perdido Street Station" is soft sci fi / fantasy. Their machines are steam powered, but they have miniature punch-card computers (good luck getting that working!) that are more sophisticated than the ones that we have now. That is to say, the power that runs through their computers is slower than electrons, the instructions that the computers use are slower than our silicon processors, and they aren't described as having memory similar to the disks or RAM that that we have today, yet their computers are capable of more powerful computation than our computers, and the author doesn't assert that magic was involved. Even more astounding, while they have more sophisticated computers, they haven't had an information revolution. Their rudimentary hardware is fantastically powerful, but they have done very little with it.
Their system of physics is also annoying. It is mostly like our physics (aside from magic, which I consider as a separate system), so when the scientist explains how something works, he explains it in a way that would make sense in our physics. Except that it's wrong. It's like the author has a high school knowledge of physics and uses that to try to explain a slightly modified quantum physics. I can accept a modified physics (indeed, in a work of science fiction, I almost expect it), but the explanation, if one is there, needs to be good. The author uses potential energy to explain fundamental physical particles, which is an incorrect analogy. Potential energy is a thought abstraction of how much work fundamental physical forces like gravity or electrostatic resistance could do to an object. For instance, if I drop a ball, gravity does work to it. When you put a battery in a computer, the electrons do work. Electrical voltage is similar to potential energy; it's like the electrons were water, the battery was a spring of water on top of a mountain, and the computer was at a lower elevation. The author explains potential energy as if were the force itself rather than the result of the force, and he uses that analogy as the basis for the explanation of his modified physics.
In other words, the explanations in "Perdido Street Station" occupy the uncanny valley where the author provides enough detail that I expect a good explanation (rather than just an assertion of faster than light travel, for instance) without providing a good explanation.
The book also suffers from some of my usual critiques: there are too many points of view, and I don't like the protagonist enough. The scientist is the protagonist. The artist and the vagabond each see a good amount of ink. There are probably also a dozen or two minor characters that only share their point of view for a chapter or two. They are each interesting, but because no one but the protagonist gets too much attention, the book only provides enough attention to tantalize and never enough to satisfy. In a few cases, this is used to good effect since it provides dramatic or tragic irony. However, the frequency with which the author skips between points of view and the sheer number of points of view is too much for the author to pull off.
It seems like the author did this to show the reader all of the action that is affecting the story, but I don't think that that is the best way to tell a story. There is room for mystery. An author doesn't need to tell the reader everything (and he doesn't tell us everything, leaving some plans secret for the sake of suspense). It is often more natural to make a story about a point of view rather than to make a story about a set of disconnected actions. It seems like the author chose to tell a story about disconnected actions and, thus, has included many disconnected points of view so that the reader can read that story. However, since I'm a very people-centered person, I usually think that a set of actions is less engaging than one person's experience with a subset of those actions. Thus the appeal of a first person story. Thus the appeal of an unspoilable story.
I also don't really like the protagonist. The protagonist is just a regular human scientist, so the author doesn't take me into an alien mind. The protagonist also seems to react to circumstances in a pretty standard way and without much attention paid to emotional affect or ethical philosophy. In other words, the protagonist lacks most of the components of a good protagonist, and the story is interesting despite, not because of, the protagonist.
That lack of a good protagonist is made all the more tragic by the compelling cast of characters. The book I want to read would not be about the story that was told in "Perdido Street Station," but about the experiences of the vagabond. The artist, the crime lord, the mayor, or the demon would have also been interesting to read about, but the vagabond is the most. He is an alien mind, he reacts to circumstances in a unique way (and he has plenty of stuff to react to!), and he has a poet's voice that spends a lot of time reflecting on emotional affect and ethical philosophy. The vagabond only gets a few pages here and there, but I would have loved to read 300 pages of first person that was solely the vagabond.
The book did not use simple words and did not pace its introduction of fantastic subjects. The book did not have a well constructed system of magic or physics. The book did not choose just one protagonist or choose its focus well. As a result, I found "Perdido Street Station" to be slow moving and not something that I would spend hours of my day reading. Despite its poor structure, the book was moderately interesting, so long as I don't spend too long reading.