Vlad Savov, The Verge:
The iPhone’s lead as the smartphone to beat has rarely been defined by just one thing. At one point, the biggest advantage was the simplicity and speed of its interface; at another, it was down to the diversity and quality of available apps; and most recently, the iPhone has distinguished itself with the quality of its 8-megapixel camera. Today, the combination of all these things — simple and fast operation, strong optics and image processing, and a wide app ecosystem — is helping people create the best possible images with the least possible hassle.
The effortlessness of taking good pictures with the iPhone is probably that phone’s most underrated quality. And yet, its importance grows with every passing day.
Also see Stephen Hackett's comments on 512 Pixels regarding Vlad's post:
Just look at the iPhone 6 and 6 Plus. I'm sure it nearly killed some industrial designers at the company to have a protruding camera, but clearly good optics were of a higher priority.