What makes an iPhone unlike anything else? Maybe it is that it lets you do so many things. Or that it lets you do so many things so easily. Those are two reasons iPhone owners say they love their iPhone. But there are many others as well. The Retina display on iPhone ushered in the era of super-high-resolution displays. Its pixel density is so high, your eye can not distinguish individual pixels. The images and words are amazingly vivid and crisp. Everything just looks so real. In fact, once you see a Retina display, you are never satisfied with anything less. Yet it remains a feature found only on iPhone and other Apple products.