Samsung's (NASDAQOTH:SSNLF) latest ultrabook, the 2015 edition of the ATIV Book 9, is already being compared to Apple's (NASDAQ:AAPL) ultra-thin laptop, the Macbook Air.

Samsung's device bests Apple's Macbook Air in a number of notable ways: It's both thinner and lighter, with a larger, sharper screen and better battery life. To be fair, it's also more expensive and newer, but its biggest weakness is beyond Samsung's control. However, there's just one probablem: it will run on Microsoft Windows. 

The noncompetitive Windows platform
For a prospective buyer choosing between the two devices, the biggest factor could turn out to be the operating systems: the Ativ Book 9, like Samsung's other laptop offerings, will run Microsoft's Windows. Apple's Macbook Air, in contrast, is powered by its proprietary OS X.

Samsung executives have been explicit in their dislike for Microsoft's latest operating system. Reacting to the steady decline in the demand for traditional PCs, the head of Samsung's memory chip division blamed the "less-competitive" Windows platform.

Samsung is not known for its software -- its TouchWiz Android skin has largely been derided -- leaving its PCs at the mercy of Microsoft.

Apple's Mac is taking share
More than 200 million Windows 8 licenses have been sold -- so despite its faults, there's still a market for Microsoft's software. Yet, the intense criticism surrounding Windows 8 seems to have benefited Apple's Macs.

Last quarter, Apple sold 5.52 million Macs, an increase of 21% from the prior year. Double-digit sales growth is always impressive, but is particularly notable given the ongoing contraction in the market for traditional PCs. According to IDC, PC shipments declined 1.7% that quarter on a global basis. To be sure, Apple's share of the market remains quite small -- about 6.3% -- but the robust growth is encouraging.

Of course, surging Macbook sales could be due to other factors -- recent improvements to OS X encourage iPhone owners to pair their handset with a Mac, for example, while Apple has dropped the price of the entry-level Macbook Air several times in recent months.

Windows 10 and a new Macbook Air
But Samsung's latest laptop could benefit from Microsoft's next operating system. Windows 10, set to debut later this year, will fix many of the common criticisms leveled at Windows 8, like the lack of a start menu and a confusing blend of distinct interfaces. If it succeeds, it could reinvigorate the Windows platform, and boost demand for high-end laptops like Samsung's ATIV Book 9.

Apple, however, is poised to respond with an updated Macbook line of its own. The Macbook Air is due for an annual refresh, but this year's model could be particularly noteworthy. For months, a variety of sources -- including DigiTimes -- have said that Apple was hard at work on an all new, 12-inch version of the Macbook Air, one that could be just as revolutionary as the original, 2008 model.

If so, it could continue to propel Apple's share of the PC market, and make life increasingly difficult for Windows OEMs, including Samsung. Sony, whose VAIO laptops were long favored among high-end Windows buyers, exited the PC business early last year. Already, Samsung has shown similar signs of weakness -- it suspended its European PC operations, though has continued to sell its devices in other regions.

Certainly, Samsung's Ativ Book 9 offers some real competition to Apple's Macbook Air, but until it can offer software on par with OS X, it's unlikely to have much of an effect.

Sam Mattera has no position in any stocks mentioned. The Motley Fool recommends Apple. The Motley Fool owns shares of Apple. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.