If buying a smartphone for its camera is your priority, then you're better off with the Nokia Lumia 1020. Seen here are picture comparisons by Robert Scoble comparing the 1020 with the new iPhone 5S. Nokia completely blows the 5S away.
The 1020's biggest selling point is its camera, which is a 41 megapixel "PureView" lens system. The iPhone 5S has an 8 megapixel camera.
Just take a look at the great low light situations with a flash compared to the 5S:
Here are Scoble's photos, which are
all on Flickr:
A photo taken with the 1020 with a flash:
Photo taken with iPhone 5S with flash: