As far as rivalries go, Apple (NASDAQ:AAPL) and Microsoft (NASDAQ:MSFT) have been duking it out for four decades. That doesn't mean the companies haven't collaborated in various ways over the years. More recently, each has outlined a distinct vision of the future of computing.

These visions of computing aren't necessarily mutually exclusive, but they are battling it out for consumer mindshare. Which one will come out on top?

Apple stands pat
For the most part, Apple's operating system strategy has been quite consistent in recent years. iOS runs Apple's touchscreen mobile devices, while OS X powers its desktop and laptop computers. The two operating systems remain quite distinct, even as feature convergence occurs and both now communicate with each other to a greater degree with technologies like Continuity and Handoff.

Source: Apple.

Apple remains committed to this approach, which also means that the Mac maker is unlikely to make any type of convertible or hybrid devices like the ones that Windows OEMs have been churning out for years. Don't hold your breath for any touchscreen Macs.

Analysts have asked CEO Tim Cook on numerous occasions whether or not the company will ever introduce a convertible, but Cook seems uninterested in those form factors given the inherent compromises. Apple's philosophy has been that in order to truly push forward into the post-PC world, iOS needs to be a fresh start, uninhibited by legacy requirements.

Microsoft changes its tune
Initially, Microsoft took a similar but slightly different approach than Apple. When Microsoft unveiled Windows 8 in 2011, the OS was set to power both tablets and PCs while smartphones would run Windows Phone. Microsoft's rationale made sense: tablets resemble PCs in many ways, arguably more so than smartphones.

At the same time, Microsoft also had Windows RT, made to run on ARM-based chips. Windows RT quickly failed, as it lacked support from OEMs and Microsoft did not properly convey the value proposition to consumers.

Source: Microsoft.

Just last month, Microsoft unified its OS strategy with Windows 10. The company had been teasing as much. For instance, on the July conference call, CEO Satya Nadella said, "We will streamline the next version of Windows from three operating systems into one single converged operating system for screens of all sizes."

Windows 10 will run on all devices and offer a single storefront for digital content. The interface backtracks on Windows 8's dramatic new paradigm, embracing the familiar Start Menu. Windows 10 also has a Continuum feature (not to be confused with Apple's Continuity) where the UI dynamically changes based on input method (keyboard and mouse or touch).

What really matters
While Microsoft has long been dominant in the realm of PCs, and is unlikely to relinquish that throne anytime soon, its share of all connected devices (including smartphones and tablets) has steadily fallen in recent years. Apple continues to grow its share in the global PC market, but its share of all connected devices is steadily rising.

As both companies' platforms will continue to coexist for the foreseeable future, there's not necessarily a right or wrong OS strategy. The real question is: which vision of the future of computing do you believe in?

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.