Let's get this out of the way: The bar for battery-case design is extremely low. Most are chunky and made of black matte plastic, requiring you to attach two pieces to your phone. You choose a battery case for utility, not fashion.

Apple's Smart Battery Case, though still fairly unsightly, is ahead of those. Bend back the top and slide in your phone. It feels just like Apple's smooth, soft-touch wraparound silicone case, except… with a protruding, awkward battery on the back. The battery juts out as if your phone will soon give birth to a rectangular alien.

Still, I'll take it over all the ugly messes sold by Mophie, Anker and others, especially since it provides better protection for the phone. A lip curves just above the screen to prevent the glass from hitting a hard surface and an interior lining provides better shock absorption than hard plastic. Plus, the grippy material is much easier to hold and doesn't feel like it will slip from my hands.

Some advice: Pick the charcoal-gray over the white, which five days in is already browning like an old gym sock.

Apple's smart battery case is fine, then, if you want a softer case or a "passive" battery charging experience, with zero control over or understanding of how the case actually charges your phone. Maybe that's what Apple is hoping: that buyers of this thing will slip it on and never take it off, charging their iPhones entirely through the case's Lightning port going forward, forgetting about its big ol' bump in the back. They will be pleased, finally, with their iPhone 6's or 6S's battery life, and the memory of spending an extra $99 for it, rather than having it just work that way in the first place, will eventually fade away.

It's fine if you don't want exterior indicator lights, or a even a case that gives you a 0 to 100 percent charge. After all, this one was designed for the iPhone, by the same company that made your iPhone. For some people, that's a big draw.

In either case this will probably sell like hot cakes. It fits nicely in holiday stockings. 'Tis the season. Just know that from a pure performance and even a design perspective, Apple's effort is not the best you can get.

The Smart Battery Case looks a little unattractive in photos, and even in person: the back of the case has a odd bulge where the battery pack lives, making it seem like a normal iPhone case somehow ate a battery for lunch. It's actually pretty comfortable to hold, though. The soft-touch rubbery silicone case is made of the same material as Apple's Smart Covers and cases, and slip-on iPhone accessories, lined with soft microfiber on the inside. It's available in two colors: charcoal gray and white.

Apple's case has a few advantages: it has a Lightning cable pass-through, which means it can be charged using your default cable, while nearly all other such battery cases require a Micro-USB cable. If it's charged with one of Apple's 10- or 12-watt iPad power bricks, it can charge the iPhone and case simultaneously for faster top-off.

Apple might be making a calculation here that many people's iPhones start to run low on battery around 5 p.m., and that they don't charge them until around 11 p.m. (That's been my experience on busy days, like during the CES trade show). So the company has calculated a case that will last exactly that amount of time to keep the size as small as possible.

Apple's Smart Battery Case for the iPhone 6/6s is the most comfortable battery case we've tested, thanks to its warm, flexible silicone material. But its smaller battery just doesn't provide as much assurance as competing cases, and it keeps you trapped in Apple's Lightning power ecosystem. For the price, we still recommend the Mophie Juice Pack Plus and the Boostcase over this one; the Juice Pack Plus will more than double your iPhone's battery life, while the Boostcase has a unique design that lets you ditch the battery part of the case when you don't need it.

It goes without saying that you have dozens, perhaps hundreds of different iPhone 6 battery case options, and no one's forcing you to choose Apple's iPhone 6s Smart Battery Case if you don't like the price, the way it looks, or the battery performance. Given the $99 asking price and 1877mAh cell, it would be near the very bottom of our guide to the best iPhone 6/6s battery cases, and I wouldn't be inclined to recommend it to most people.

That said, if the Apple name or the unique dual battery Lock Screen feature are of interest, you like the way it looks, and you're willing to pay a premium for the package, this isn't a bad battery case. Apple clearly could have done better, and hopefully, it will learn some lessons from this model for next year's inevitable iPhone 7 sequel - or better yet, improve the "smaller" iPhone's internal battery so that accessories of this sort are no longer necessary.

Apple's first battery case works, and it works well. Here's the rub, though: There are plenty of cheaper, more capacious options, and some of those are prettier too. What the Smart Battery Case offers over its rivals is a sense of cohesiveness that stems from Apple controlling both the hardware and software experience. The convenience of a Lightning pass-through for easy data transfers and power reminders in iOS might make the case's $99 price worth it for some of you, but everyone else could spend half that on a third-party case.

I've tested a lot of battery cases: waterproof ones, slim ones, ones with high-battery capacity, cheap ones, expensive ones, you name it. They all do the job and so, if you only see yourself needing a battery phone case a couple of times a year, opt for a more affordable option.

But if you imagine yourself needing extra iPhone juice day in and day out, I'd recommend Apple's Smart Battery Case. The flexible silicone cover is a huge advantage over other cases. Pulling the iPhone in and out is a cinch, and the buttons aren't sticky like most offerings.

The battery bump in the back is kind of …awkward, but I really like that even my tiny hand can wrap around the phone without feeling like it's bulky. Many cases feel like you're carrying a brick around – this case does not.

Just like you can find cheaper phones than the iPhone, cheaper smart watches than the Apple Watch, and cheaper computers than the Mac, you can find cheaper battery cases than the Smart Battery Case. You just typically can't find them with the same level of materials, manufacturing, and integration. Those come with the Apple logo on the back.

Beyond that, though, Apple is doing something novel here: efficiency. The company is trying to get the absolute most power from the absolute least battery. Bigger is heavier and that comes with a cost in the hand and the pocket or purse. Apple's case is for those who need a little extra juice some of the time, but want to be weighed down and bulked up as little as possible. That's what they're solving for.

If you don't care about any of that, then you should absolutely buy something else. There are plenty of alternatives available for people who want lower prices or bigger batteries.

Apple makes their version for people who want Apple's version.

Putting it bluntly - there's no reason to go with the Smart Battery Case unless you need something like it the moment you buy your iPhone and, mysteriously, no other option is available. It does what it needs to do, but at a high pricetag and with problems other casemakers solved years ago.

It's a shame, since the case's Lightning port and iOS integration is genuinely useful and sets it apart from the pack. Hopefully this is the harbinger of the technology coming to superior third-party accessories.