This review was adjusted on October 31st in light of confirmed physical vulnerabilities in the Kevo's deadbolt. We're working on a revised video as well, so please stay tuned.

Keys. Who needs 'em?

Not the Kwikset Kevo, that's for sure. With the Kevo (licensed out from UniKey), you'll be able to unlock your deadbolt just by tapping on it, thanks to the built-in Bluetooth 4.0 capable of detecting the smartphone in your pocket. Don't have a smartphone? Don't worry about it -- the Kevo comes with a handy keychain fob that'll let you tap your way inside, too. You can even use the free Kevo app to send friends and loved ones "eKeys" to let them in when you're not around. And for purists, rest assured that the Kevo still functions like a standard mechanical lock, with keys and everything.

This idea of smartening up our deadbolts is something we've heard a lot about for the past year or so, with upcoming products like the Lockitron , August , and Goji striking it big through crowdfunding and good old-fashioned word of mouth. But talk is cheap, and smart locks are expensive -- $219, in the Kevo's case, about seven times the cost of a standard Kwikset deadbolt. Is kissing our keys goodbye really worth such a price?

I certainly wasn't convinced that it was -- but then, I got my hands on a Kevo to try out for myself. After installing, calibrating, and testing the thing out, I was thoroughly impressed by how strongly the Kevo performed. That said, a smart lock is still a lock, and as brainy a deadbolt as the Kevo is, I wish that it were a bit brawnier, too. Despite being bump-proof and essentially pick-proof, our tests confirmed that the Kwikset SmartKey deadbolt that makes up the guts of the Kevo is vulnerable to certain types of simple forced entry.

As such, if you're looking for the strongest, safest lock on the market, I think you'll want to look elsewhere. But, if you want a lock that's loaded with convenient functionality and an undeniable cool factor, then look no further.

Colin West McDonald/CNET

It's the little things

Tapping your way into your home has some clear appeal, especially if you're carrying an armful of groceries. Surprisingly, some of the Kevo's best features are its least noticeable.

First, Kwikset seems to have eschewed the kinds of design touches emblematic of an expensive device, and considering the fact that this is likely going to sit on the outside of your home, I'd say that's wise. I'm not sure that I'd feel comfortable bolting a conspicuously fancy appliance to my front door, as you will be if you go with a lock like the Goji. Unlike those kinds of sleek, modern, space-age-y smart locks, the Kevo looks like any other boring deadbolt. By not advertising itself as a pricey piece of hardware, it isn't likely to draw unwanted attention to your front door.

You can only really tell this lock is special when you touch it. When that happens, a ring of blue LED lights will spin around the lock, indicating that it's thinking about whether or not to grant you entry. If it detects your phone or your fob's presence, the lights will turn green and the lock will open (if you're locking it, the lights will turn yellow.) If your phone or fob is too far away for the Kevo to key in on its precise signal, the lights will turn magenta, telling you to stand a bit closer and try again.

The magenta lights mark another subtle, yet strong design feature. They'll only appear if the Kevo is certain that you're outside. If it thinks there's even a chance that you're inside your home, it'll only show the spinning blue LEDs, then nothing. Why is this important? Let's say you're inside the house and someone unsavory is at your door. If not for the inside/outside distinction, they could simply tap the lock, see the magenta lights, and know that you're nearby inside. It's a little touch that highlights Kwikset's commitment to your privacy and security.

Colin West McDonald/CNET

Calibration is key

The Kevo determines whether you're inside or outside your home thanks to a clever calibration process that teaches the lock how to make the distinction. It's perhaps the Kevo's most crucial feature -- without it, leaving your phone sitting on a table near the front door would mean that anybody with skin could waltz up to your stoop and unlock your deadbolt. It's the number-one thing that I wanted to test out, and thankfully, it's a feature that works flawlessly. I tested it again and again, from every conceivable angle, and not once did the Kevo unlock when I didn't want it to. Kwikset errs on the side of safety here -- you'll basically have to stand right on your doormat in order for it to reliably recognize you 100 percent of the time. Take a step to the left or a step to the right, and that number will drop to 80 or 90 percent. Leave your phone inside, even right up next to the door, and it drops to 0 percent.

According to Kwikset's instructions, calibrating the indoor/outdoor detection seems like it should be painless enough -- just tap the calibrate button on the indoor side of the lock, hold your device against the lock for a few seconds, then step outside. The lock will glow green, and, with the phone or fob that you're calibrating in your pocket, you'll simply tap the lock three times. That's it.

Except that really isn't it. After those three taps, the lock will either flash green for a successful calibration, or red for an unsuccessful one. As simple a process as it sounds, it took me about a dozen attempts to get it right. I tried doing it with my phone in my pocket, as instructed. Red flash. I tried holding the phone up in the air. Red flash. I tried stepping back as far away from the lock as I could. Red flash. Nothing seemed to work. Finally, I tried it with my phone tucked into my shirt pocket, putting it at roughly an even height with the lock, and this got me the green flash.

I spoke with some of the folks at Kwikset about this, and they acknowledged that calibrating can take multiple attempts to get right. They're aware that it probably isn't as easy as it should be, and to their credit, they've done about as good a job as they can of managing the issue. The Kevo's manual is very clear about the importance of calibrating, and it walks you through the process with illustrated step-by-step instructions, warning you outright that you might need to try repositioning the phone a few times in order to see green. If, after multiple attempts, you can't get it to work, there's also a number you can call for help. Additionally, all of these step-by-step instructions are located conveniently within the Kevo app.

Screenshot by Ry Crist/CNET

About that app...

Once you're up and running, you can use the Kevo app to send eKeys to friends, family, and anyone else who may require entry into your home. These eKeys are really just an e-mail message instructing them on how to download the Kevo app and authorize their phones to open your lock. You'll be able to see when people "accept" the eKeys you send out, and you'll also be able to see when everyone is coming and going on a handy timeline. If needed, you'll also be able to delete or temporarily disable those eKeys, too.

However, unlike with some other smart locks, you won't be able to send out eKeys that only work at a certain time, or that automatically expire on a certain date. You'll need to manage all of that manually, which is a little bit disappointing. Also a bummer: each eKey you send out after the first one will cost $1.99. This doesn't bother me that much -- after all, that's about what you'd pay to get a normal key copied. Still, copying a normal key requires parts and labor. Charging for eKeys is just something that Kwikset does because, well, it can.

Another minor quibble is that your iPhone will vibrate and make the "new mail" sound whenever you activate the lock. I like feeling that buzz in my pocket and knowing that the process is working, but the app doesn't currently offer a way to change the sound, or mute it completely. Look for that to change in the near future as the app gets updated.