These are 100 percent crops from the inset photos. At small sizes, all of the photos look good, but the iPhone 5 is the clear winner with detail, color, and exposure once you start to enlarge.
All three of the phones were very good at shooting close-ups. These are 100 percent crops of the inset images. The only issue I had was with the focus on the One X (middle), which seems to have focused just above where I tapped. However, that might have just been user error.