If you're looking for a real-world comparison of the iPhone 5's camera versus the 4S, check out this series of photos on TREK. Photog Austin Mann took some 5's to Iceland to test them out.
Low-light photos look great and show considerably less noise than the 4S. It's probably not as great at Nokia's upcoming Lumia 920, but we'll wait for Engadget to test the 920 head-to-head.
Mann also tested the iOS 6 panorama feature, noting how fast and easy it is to use.
Perhaps most intriguing: the iPhone 5 fared well in durability. From Mann:
"Late September in Iceland is not a friendly place for any electronics... this is a time that puts your gear to the test whether you like it or not. Just in the last two days of shooting here, I've had my iPhone 5 covered in water from shooting near a waterfall and Jordan has dropped his directly in the mud. Both seem to be working fine."
That's good news to someone who dropped his 4S the first week he got it. I can't wait for my 5 to arrive this Friday.