I've always heard good things about that The City and The City. I'll have to try it. Though I find Miéville a bit difficult to read. I mean, I loved Perdido Street Station as a whole, but I had to be in the right mood to fully absorb it. It was pretty dense.
The City & the City is amazing, and this is coming from someone who's hated every other Mieville book he's tried. Just a really great concept which is explored nicely through plot, unlike Mieville's other work which usually ends up feeling like a sourcebook rather than a novel to me.