Apple does this every other year with iPhones -- see the iPhone 3GS and iPhone 4S. It's a common occurrence in iPads and MacBooks, too: take a familiar form, and repeat. But, in a phone landscape dominated by rapid change, it can feel frustrating, even for a product we loved just 12 months ago. Even iOS 7, Apple's graphically overhauled operating system, feels different but not really all that shocking. Even the new colors -- gold and "space gray" -- are subtler than you realize.

That doesn't mean there aren't changes, but many of them seem like roadwork for the future; a cleverly ingenious under-the-home-button fingerprint sensor, a clearly better camera, majorly upgraded graphics, a motion-tracking M7 coprocessor, and a new A7 processor capable of 64-bit computing are a lot of under-the-hood tweaks. But, after a week of using the iPhone 5S, it's hard to find situations that currently take advantage of these features, except for the fingerprint sensor and camera.

Check back in two months; after new apps emerge, maybe the iPhone 5S will start seeming like a truly new iPhone. But, for now, it's more of refined improvement. The iPhone 5 has gotten better. How much better depends on how fast apps and services can take advantage of the features...or whether we'll be waiting until iOS 8to see them truly take shape.

iPhone 5 and 5S. Can you tell the difference?

The 5S is a carbon copy, with some new color variations. You can get last year's white/silver color, or "space gray," which matches black glass and a darker gray anodized aluminum. And, yes, there's gold. But it's not like a prop from Liberace's home: it's mellow gold, more a champagne, or a light bronze. Paired with white glass on the back and front, you might have a hard time noticing the gold in the wild unless it was held in the sun. Of the three colors, I liked gray the best: the metal tones might do a better job hiding scratches, too, a problem I saw pop up on last year's all-black iPhone 5.

A year later, the iPhone 5's design still feels sleek and high-end in the 5S, great in the hand, and more compact than most competitor phones. But, it also has a smaller screen (4 inches) than most of its Android cousins. I love using a more compact phone, but competitors have found a way to make larger-screened 4.7-inch phones with excellent feel, like the Moto X, which has nearly edge-to-edge screen across its face. The iPhone 5S has a lot more bezel framing the display, and I couldn't help wondering if that screen couldn't be just a bit bigger.

A larger screen would have really helped this year: not because the competition has it, but because Apple's newest features and apps would put it to good use. I found editing and appreciating the improved photos and video recording, and even playing games, to be challenging; the better that graphics and camera quality get, the more you need a larger screen to appreciate them.

Camera

Touch ID may be getting all the headlines lately, but the iPhone 5S' improved camera is probably its biggest selling point. Cameras are no longer afterthoughts on smartphones: they're becoming the most important feature, for many, as they slowly but surely replace point-and-shoot cameras.

If you're getting a new iPhone for its camera, get the 5S. A suite of new and useful upgrades help make the already-good iPhone 5 camera into something even better...but, in a landscape riddled with increasingly impressive phone cameras, the iPhone stands out a little less than before.

Unlike many megapixel-packing smartphones (41-megapixel Lumia 1020, I'm looking at you), the iPhone 5S camera stays at 8 megapixels, the same on paper as last year and even the year before. The sensor, as Apple will proclaim, however, is 15 percent larger: the pixels are physically bigger (1.5 microns), even if there are the same number of them. The camera's aperture is larger (f/2.2). All of these elements add up to better low-light exposure.