The oft predictable Apple mixed things up a bit this year by releasing not one, but two handsets: the iPhone 5s and the 5c. As an incremental update, the flagship 5s borrows heavily from its predecessor which in theory would encourage many to play the waiting game for one more year to see what sort of new design Cupertino comes up with for the iPhone 6.

You wouldnít know itís an incremental update based on early sales figures, however. Apple managed to move more than nine million iPhones during launch weekend a few weeks ago and early reports suggest the 5s was the top-selling phone at all four major US carriers in September -- surprisingly, it's the cheaper 5c that is not doing as well. That said, there is some new technology inside the 5s that is partly responsible for its early success, namely the all-new 64-bit A7 processor and the Touch ID fingerprint reader built into the phone's Home button.

Hardware & Design

Only a couple of subtle design changes clue you in as to whether youíre looking at a 5s versus last yearís model. The new phone retains the same two-tone aluminum and glass construction, the same 4-inch Retina display operating at 1,136 x 640 pixels (326 ppi) and identical button placement.

The display looks as good as ever (although perhaps a tiny bit warmer than the iPhone 5) and while the 4-inch phone fits nicely in my smallish hand, I really would like to have seen something larger from Apple. I suspect this will come with next yearís iPhone 6 as Cupertino has likely held onto the idea of a small, pocketable phone for about as long as they can. Something in the 5-inch range seems plausible as virtually every Android on the market now ships with a screen size in this range or larger.

If youíre coming from a 4s or a different brand of phone altogether, youíll likely immediately notice how lightweight the iPhone 5s feels in the hand. It weighs just 112 grams yet given the superb glass and aluminum construction, it feels very solid although its squared-off edges arenít the most comfortable when holding for a long period of time.

The headphone jack is still positioned on the bottom of the phone which may seem like an odd choice until you realize that whenever you put your phone into your pocket, you naturally do so with the top facing down. This would make listing to music with the included EarPods much more convenient although at other times, it could be a nuisance.

Only the redesigned Home button with embedded Touch ID sensor and the addition of a second LED flash on the rear of the phone indicate this is a new iPhone model. On one hand, this is a good thing as existing iPhone 5 accessories like cases will still work with the 5s, but at the same time, you arenít getting a flashy new handset that will grab attention like a completely redesigned phone might.

The 5s is available in three different colors: Space Grey, Gold and Silver. Everything else Ė from the dimensions and the weight of the phone to the speaker grill layout Ė is identical to the iPhone 5.

The Touch ID fingerprint reader is built into the Home button. A metallic ring encircles the Home button which is a bit less concave and no longer has an icon printed on it. This sensor can be used to unlock the phone, thus eliminating the need to enter in a passcode each time you want to unlock the device (you do use a passcode, right?). Additionally, Touch ID can authorize iTunes purchases with a single tap.

My past experiences with fingerprint readers like the ones that shipped with notebooks for a spell had led me to the conclusion that they were little more than a gimmick. Touch ID has changed my mind. It is far and away my favorite feature on the 5s and is extremely convenient if you need to access your phone multiple times a day.

The initial setup process takes a minute or two to complete. You are asked to place a finger on the sensor and hold it for a moment then lift and repeat. During this time, the sensor is scanning the complex contours of your fingerprint and once complete, youíll be able to use that digit to unlock the device and authorize purchases.

You can add up to five fingerprints Ė either all yours or the prints of someone you wish to share the phone with. The system is nearly flawless in its implementation as it will recognize a finger even if it is turned completely upside-down. I had several friends try to unlock the phone using their prints; all failed. The only time the system didnít recognize my own print was if my finger was damp. Otherwise, it worked every time.

As weíve learned in recent weeks, there are methods to circumvent the sensor but given the complexity of those measures, itís not likely that itíd be worth the time and effort to do. And the good thing about fingerprints is that you canít forget them like a passcode. Whatís more, those concerned that Apple is building a database full of iPhone 5s usersí fingerprints donít have to worry as all prints are encrypted and stored locally on the device in a secure area of the CPU.

The only shortcoming Iíve discovered is that Apple forces you to select either Touch ID security or a passcode, but not both. For the uber-security conscious users out there, two-factor authentication could have added a bit more peace of mind.

Meanwhile, the other recognizable new hardware feature is the dual-LED flash that is part of a system Apple calls True Tone. Apple claims the added amber/warm light flash can be used to produce more accurate skin tones when snapping photos using the flash. It sits just below the original flash in a vertical orientation Ė the phone evaluates lighting conditions in real time and flashes each one at varying intensities for the best possible results.