The rest of this post will involve minor spoilers, but I can't list the other books because that list would effectively act as a spoiler by itself. Still, nothing here should affect your enjoyment.
The key concept of this book is that there are two overlapping cities. Imagine that you had London 1 and London 2, and a given building would only belong to one of these cities. Some streets are also city-specific, while others are shared. If you live in London 1, you only interact with other people/architecture in London 1, so you will ignore everything in London 2, and vice-versa. People walk around and basically pretend that half of the city doesn't exist. If you live in London 1, and your next door neighbour lives in London 2, you can't simply knock on his door; instead, you have to drive to border control, show your passport to get into the other city, then drive back the way you came, now ignoring everything in London 1.
Why does all this happen? I don't know. The book said that even the characters aren't clear on the origins of the cities: it may have been one city that split in half, or it may have been two separate cities that merged together. Fair enough, I'll accept that, but I don't accept that people would put up with such a mind-bogglingly stupid arrangement unless they actually had a reason for it.
By contrast, look at Neverwhere (by Neil Gaiman). The idea there is that people in London do their best to pretend that homeless people don't exist, so eventually the homeless become invisible: they can still see everything around them, but people in London Above are oblivious to London Below. That's fine: it basically involves magic, and I don't think it's really plausible, but I'm happy to go along with the premise.
Or take Midnight Nation (by JMS). There's a similar concept, where people "fall through the cracks", so they're invisible to society. However, in this case it's symmetrical, i.e. the people who've fallen through can't see normal people either. In fact, they seem to be effectively intangible, so they can cross the road without getting squashed by invisible cars. This involves some religious/mystical ideas, e.g. that your soul can be removed from your body, and I'm happy with that.
This is similar to the sci-fi idea of people being "out of phase". Star Trek TNG did that in one episode (The Next Phase), and so did Sliders (Gillian of the Spirits). Again, there's an explanation for this, even if it's just technobabble, and there's a sensible motivation for everyone else to ignore particular characters (i.e. they can't see them), so I'm happy with that.
Stardust (Gaiman again) is a bit different, but it's a related idea: there's a particular field where our world overlaps with the Faerie world (next to the town of Wall), so people can meet there once a year to trade goods. Outside that field, each world has its own separate geography, so there could be two cities which effectively overlap but don't interact. Again, I'm happy with that.
The point is, I'm not picky. Give me something, anything, and I'll play along, but I'm not willing to accept an arrangement like this without any explanation, and I think it's unreasonable for the writer to expect me to.
I read another of Mieville's books a few years ago (King Rat), because he was a Guest of Honour at Picocon. I thought it was alright; it reminded me of stories by other people (possibly Gaiman), but he handled the themes in a less pleasant manner. Since I've paid for this book, I'll read the rest of it, but I don't recommend it to anyone else.