Some of my colleagues have been using iOS 7 since the first betas arrived from Apple in June, but I actually didn’t start until September 18, the very day it was released as a free download. Since then, the number of users has reached the hundreds of millions, signaling the fastest upgrade of any mobile OS — ever!
While every iOS release has arrived with an assortment of bugs, they seem more numerous with iOS 7, since it’s, visually at least, a sea change from previous versions. The slim and elegant text puts off some, because it may not be quite as readable. Others are freaked over the parallax effect from the few dynamic backgrounds Apple provides, or the constant zooming effects.
In fact, some people claim to have gotten dizzy or suffered from motion sickness over the special effects, and thus crave for a way to minimize or eliminate them. Now some of this is already possible. There are Accessibility options to reduce motion and contrast, which help some. You can also switch to bold type, which helps if visibility is an issue.