Back in London in the early 80s, I frequented two great SFF bookstores: Forbidden Planet, and Dark They Were and Golden Eyed. In looking up the source of the latter's name (a Ray Bradbury story) the other day, I was surprised to learn that Stan Nicholls had worked at both. So that's a point in his favor right there.
One of the things that Nicholls does very well is to not only create interesting, credible characters, but to keep the story moving smoothly across many fronts at once. He does this latter as well as anyone I've ever read - there are a lot of moving pieces, but it's never confusing as the narrative moves around. It would have been nice to have a map, but you can't have everything.
Nicholls does less well with some other aspects of the story. Magic is related both to mysterious, vanished Founders, and to raw magic that flows around the country in underground streams. So far, so interesting. But the application of magic is sadly disappointing. Nicholls uses magic to blatantly copy modern technology, and I sometimes had the feeling what he wanted was to be writing a police procedural. Without much explanation, magic provides a visual APB for the cops, a 3D 'Wanted' poster, timed fuses, and other handy devices. Characters talk about terrorists, setting fires with accelerant, and the cell structure of the resistance movement. A secret agent is for some reason named "Geheim" (German for "secret"). But this is epic fantasy, not urban, and there are simply too many of these ill-fitting terms and tools to swallow.
It's a shame about the terminology and magical technology because the story is otherwise very well done. This is my third time through this book. Once when I bought it, another re-read some years later because it had stuck in my head, and now because I've finally tracked down books two and three. Three readings tells you something right away. Even so, as I re-read it, I kept running across clever bits (e.g., the prince who fears Death so much that he and his whole court are constantly on the run), and thinking "Was that in this story?" There are at least half a dozen such clever ideas, neatly integrated into the story. If Nicholls had taken the time to work out more credible magic, the book would have been a deserved classic. As it is, it's good, but not great.
Overall - well worth reading if you're looking for well-written fantasy and can overlook frequent use of pseudo-technology. For myself, I'm looking forward to reading books 2 and 3, but I'm not yet convinced that I should move on to Nicholls' more famous series, Orcs.