If you're shopping for a new iPhone this holiday season, Apple has two new handsets to choose from. The iPhone 5s is the higher-end model, but are its upgrades worth the extra US$100? Or do you thumb your nose at its "forward-thinking" features and go with some fun new colors instead? Let Gizmag try to help, as we go hands-on to help you decide whether you're better off with the iPhone 5s or iPhone 5c.

Better or more colorful?

When we took a closer look at the iPad Air and Retina iPad mini, we were basically dealing with the same tablet in two different sizes. That isn't the case with the iPhone 5s and 5c. The 5s has a faster processor, an extra motion-tracking processor, a better camera with some new features, and a fingerprint sensor. It's the more advanced iPhone, period.

The iPhone 5c, meanwhile, is basically an iPhone 5 (Apple's 2012 flagship) in a colorful plastic shell. In fact, the 5c replaced the iPhone 5 in Apple's lineup, sending it to an early grave after just one year. So if you take appearances out of the equation, we're pretty much comparing "this year's iPhone" to "last year's iPhone."

I think the iPhone 5c feels great in hand. This isn't the flimsy plastic that Samsung uses on most of its phones. If you ever used the old iPhone 3G or 3GS, I think the 5c feels like a lighter, thinner, much more colorful version. Its polycarbonate body is very solid, with sloped edges. "Smooth" and "buttery" are my best descriptions for how the 5c feels in hand.

And then there's the color. Apple sells the iPhone 5c in green, blue, pink, yellow, and white hues. They're lively, vivid, and playful. They spice up what has been, until now, a lineage of black and white iPhones. If you're more interested in the look and feel of your phone, that might be all the upgrade you need.

If the 5c is last year's iPhone with a new look, then the 5s is the exact opposite. It looks almost exactly like the iPhone 5 did, including its razor-thin aluminum body, with flat back and chamfered edges. It even weighs the same feathery 112 g (3.9 oz). The only visible differences between it and last year's iPhone are its new home button, a dual LED camera flash, and two new colors (space gray and gold join the 2012 carryover silver).

In hand, the 5c is a little heavier than the 5s (by 18 percent). It's also 18 percent thicker. Unless you're holding them each at the same time, though, you probably won't notice much of a difference there. The 5c isn't by any means a heavy or thick smartphone; it just isn't as razor-thin or ridiculously light as the 5s.

Otherwise the 5s and 5c have a lot in common. They both have the same 4-in Retina Display (1,136 x 640 at 326 pixels per inch). They're also the same height and width. They both support 4G LTE and run iOS 7. Battery life is similar too, with the 5s only having a slight edge. With regular use, I've never come close to conking either out before the end of the day.

Though performance is technically a big advantage for the iPhone 5s, in regular usage right now, I don't think it makes for a huge difference over the iPhone 5c. The 5c is a speedy phone in its own right, but the 5s is better prepared for future 64-bit apps that will take advantage of its A7 chip. It's a much better choice for future-proofing performance. But today, at this moment? Don't expect to pick up both phones and see much of an obvious speed boost in the 5s.

So the two phones aren't all that different. But we aren't here just to talk about how similar they are. We want to break down the perks that each offers. Let's shift gears and take a look at the big exclusive features that you can only get from the iPhone 5s.

iPhone 5s exclusive #1: Touch ID

One of the biggest reasons to choose the iPhone 5s is its Touch ID fingerprint sensor. Touch ID is all about blending security and convenience. When setting up Touch ID, you'll press your finger on the sensor multiple times (guided by onscreen cues) until it "learns" your fingerprint. You'll also set up a passcode. From that point on, you can unlock your phone with your fingerprint. Anyone else needs the passcode to get in.

If you already use passcodes, then Touch ID is going to make things much easier. And if you're like me and never bothered with passcodes, then you can finally get the security you've been missing without adding the hassle you've been avoiding.

In my experience, Touch ID works well almost all of the time. Tap the home or power button to awake your phone's lockscreen, then hold your finger over the sensor. Usually in less than a second (never longer than two seconds), your phone will unlock. You can also use your print to authorize App Store and iTunes purchases. This is the fingerprint's first move in its mission to replace the password.

The only problem I've had with Touch ID was related to living in a dry climate. Sometimes my fingers get ashy and peely, and Touch ID would occasionally reject my print. But two things have almost completely solved this issue. First, I've discovered a magical product called hand lotion. Second, since you can teach Touch ID to recognize up to five fingerprints, I entered by right thumb twice (focusing on slightly different parts of the finger each time). Now even when my finger gets drier than usual, the sensor usually accepts it.

Touch ID will soon be on all new iOS devices, so it might not be worth upgrading just to get it now. But if you do buy the 5s, it's one hell of a handy feature to have. There's also a good chance that it will do much more down the road. If Apple eventually lets third-party apps sync up with the sensor, you may never need to enter a password or credit card number on your iPhone again.

iPhone 5s exclusive #2: Improved camera

On a technical level, the iPhone 5s' camera has a larger sensor, wider aperture, and better light sensitivity. But in regular photography, I noticed very little difference. In fact, I was planning on including a bunch of side-by-side camera samples, but almost all of them were indiscernible. Maybe I just didn't find the right setting or lighting conditions to let the 5s' camera's shine, but I saw little reason to recommend upgrading there.

Where the 5s' camera does shine is with extra photography features that the 5c doesn't have. One of the coolest is slow-motion video. It can record 1080p clips at 120 frames per second, which are automatically slowed down to 25 percent playback speed. If you have pets or children, or attend a lot of sporting events, this can be a blast to play with. I could watch my dog catch balls and shake off in slow motion all day long.

The 5s also has an exclusive burst mode that fires off countless shots in rapid-fire succession, then automatically picks the sharpest shot. This is also good for sporting events, or for occasions where you want to get the ideal shot as quickly as possible.

The 5s' last big camera exclusive is its dual LED flash. The two LEDs (as opposed to the one LED in the 5c's flash) light your subjects more evenly. The result is that those typically washed-out flash photos become something you might actually want to use.

If you don't have a big need for slow-motion video or burst mode, and you rarely take pics with the flash on, then you'll gain little by choosing the 5s over the 5c. If any of those features float your boat, though, it can be a pretty big upgrade.

iPhone 5s exclusive #3: Silent motion tracking

The iPhone 5s also has an M7 "motion co-processor" that's dedicated to logging motion sensor data. It can track your fitness activity in the background and send that data to compatible fitness-tracking apps and accessories.

If you do any kind of fitness tracking, this is extremely handy. When walking our dog, my wife and I often run a pedometer app to see how much exercise we're getting. On other phones, that means remembering to open the app to start tracking, and then remembering to open it again to stop it after the walk is over. It puts a hurt on battery life, and if you forget to start the tracking, you have no idea how far you went.

With the iPhone 5s, M7-compatible apps like RunKeeper will automatically log every walk that lasts longer than 15 minutes. No need to open the app before or after. Just check it sometime after the walk is over, and the workout info will be waiting for you. And it does this without draining your phone's battery.

Like Touch ID, I'm not sure if you'd want to upgrade just to get the M7 motion tracking capabilities. But if you're already thinking about the 5s, it's a nice bonus. And also like Touch ID, the iPhone 5c doesn't have it.

The better buy?

So those are the big areas where the iPhone 5s has a leg up on the 5c. But what does the 5c have on the 5s?

Well, it has ... colors. There's also a $30 plastic case, made by Apple, that's filled with holes. That pretty much sums up what we're looking at here. The iPhone 5s is improved technology, improved experience, and rides the leading edge into the future. The iPhone 5c is image, lifestyle, and the guts of a 2012 phone that still holds up quite well a year later.

Of course there's also the 5c's $100 cheaper price tag. But just remember that if you plan on signing a two-year contract with your carrier, that's just a drop in the ocean compared to what you'll be paying over the course of that agreement. The 5s doesn't offer a dramatically improved experience right now, but halfway through that contract, there should be more apps that take advantage of its superior hardware. It has more potential for growth via software updates.

If you're still on the fence, we have individual reviews of both the iPhone 5s and iPhone 5c that go a little more in-depth with each handset. You can also check out our hands-on comparison of the 5s to the Galaxy S5 or our latest Smartphone Comparison Guide, which adds a few other high-profile handsets to the mix.

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