Cameras are more or less a wash, megapixel-wise. Both main cameras collect 8 million pixels, and Google's front sensor gathers 1.3 MP to Apple's 1.2. The real magic comes in the way of software, and both companies offer lots of whiz-bangy features.
The iPhone 5's software supports panoramic pictures totaling 28MP in size. We're not sure of the pixel count, but Google's enhanced panorama mode -- called Photo Sphere (pictured) -- adds up-and-down dimensions to the normal left-and-right panoramic views. Google also launched a Photo Sphere development community and Photo Sphere website for contributing images from all over the world. We haven't tested the Nexus 4 camera ourselves, but Apple's dynamic smart filtering performs extremely well in low-light situations, and it has a sapphire crystal lens protector to help keep shots clear. Apple's camera software can shoot stills while also shooting video, and its 1080p front camera is HD capable.