It's great, really good.
Scale, scale, scale. It has this really good scale thing going on. It's tall and narrow and crowded, y'know, like a city. (It's also free which is not at all like a city but bloody brilliant all the same.)
Graphics (by Pentagram) are really part of the exhibition. Integral to it, as you can see below.
But the real star of the show are these 3D visualisations of city density. They're amazing. Dynamic, representative, appropriate. Worth the trip alone.
The other thing that struck me was how quickly these satellite style of images have entered the graphic language of 'city'. How familiar they seem now, when, visually, they're actually very unreal. You never actually see a city like that.
It's hard to explain what the exhibition is about. This Flickr set should help. Just go.