When it comes to consumer electronics, the discussion usually revolves around faster, sleeker, smaller, cheaper.
In an increasingly mobile world, though, the most important characteristic may be longer -- as in, how long the battery lasts between charges.
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And longer is what makes Apple's latest MacBook Air worth talking about. Utilizing new, lower-power chips from Intel, the Air takes battery life to places it's never been on a lightweight laptop computer.
Earlier MacBook Airs broke new ground in both portability and performance, with solid-state chips in place of mechanical hard drives to store programs and data. Using Microsoft's Windows 8 operating system, Samsung, Sony, Toshiba and others have since produced even thinner and lighter models.
No one, though, comes close in longevity -- and won't until the new chips become standard.
The base-model 11.6-inch MacBook Air retains the $999 price tag of its predecessor, but doubles the amount of storage to 128 gigabytes; a 256-gigabyte version pushes the price to $1,199. The larger Air, which has a 13.3-inch screen, costs $100 less than last year: $1,099 for 128 gigabytes, $1,299 for 256.
Externally, the new models are indistinguishable from their predecessors. They have the same striking machined-aluminum bodies and wedge-shaped designs, only .11 of an inch at the thinnest point, and weigh just 2.38 pounds and 2.96 pounds.
The big change is under the hood. Primarily thanks to Intel's new "Haswell" generation of chips, the 13.3-inch MacBook Air can go up to 12 hours between charges, according to Apple, while the smaller unit lasts up to nine hours.
I cranked up the brightness on my 13.3-inch test device -- equipped with an i5 chip, four gigabytes of system memory and 128 gigabytes of storage -- disabled power-saving settings, made sure Bluetooth and Wi-Fi were both active and launched a constant stream of Netflix movies and TV shows.
With all that, I managed from nine to more than 10 hours of use, suggesting that the company may be slightly understating the battery life you'll see in the real world.
The Haswell chips actually clock in marginally slower than the processors used in previous-generation Airs. But you'd never know it, perhaps because of other changes Apple has made, including using new, faster flash-memory chips to perk up the process of accessing and storing data, plus speedier graphics.
The Air also supports 802.11ac, the latest and fastest Wi- Fi connection. Because the standard is new, few people yet have routers that will allow them to take advantage of the greater speeds. Over time, though, users will see faster downloads and enhanced range.
Although the MacBook's design holds up well against newer competitors, there are still a couple of areas that could stand improvement.
Chief among these is the screen, where the Air continues to lack the ultrasharp Retina display found on Apple's MacBook Pro, to say nothing of iPads and iPhones.
The Air's screens are still very nice: The smaller model has a resolution of 1366 by 768 pixels, the larger 1440 by 900. But to get a better display, you'll have to move up to the heavier, costlier Pro -- or to competing models like the Toshiba Kirabook or Google's Chromebook Pixel.
Of course, a better display would also consume more power, reducing the new Air's chief advantage over those rivals. So maybe it's a trade off worth making.