Some of the first comparison shots I have seen from the iPhone 5, thanks to John Gruber for posting them on Flickr. To my eye two things are readily apparent:

1. The low-light photos are amazingly better.
2. I have mixed feelings about the photos of the City Hall. On the one hand the iPhone 5 photo is far more useable, but on the other it seems the metering for the shutter speed is causing highlights to be more blown out when the subject is rather dark. There’s always bad with the good and this seems like bad that could be mitigated with Camera+.