Every feature of the iPhone 5S is carefully considered, meticulously crafted, and works flawlessly. The device, the OS, and the ecosystem of apps and accessories are hands down the best.
In exchange for pocket-ability and single handed use, Apple has traded-off display size. For those of us who own tablets, this is a preferable trade-off. For those who only own a smartphone, a bigger display may be preferable. To those folks, I say wait for the larger screen iPhone due out later this year. You will be rewarded for waiting.