My biggest grip with iOS 7 is the fact that fonts are very thin and hard to read, especially once you’re out in natural light. But there’s a way you can improve the readability of fonts; it’s not very obvious.
Tap on Settings, then General > Accessibility, and tap the slider next to Bold Text. Your iOS device will have to restart (but it’s a quick restart). Here’s how it will look. On the left, the original font weights on my iPod touch, and on the right, bold fonts on my iPhone. If you want to be able to read your iOS device more easily, you’ll make this change.