So what does it have? Above all, it has the software and marketplace muscle of the titan of Redmond, Wash. And fans of the latest version - Windows Phone 7 - say it deserves more attention than its distant fourth-place position suggests.
"Everybody I've talked to who's using a Windows phone is really in love with it," says Lance Ulanoff, editor-in-chief of PC Magazine, which gave the Windows Phone 7 a thumbs-up review last fall when the new operating system was released.
Windows Phone 7 was a total reboot of Microsoft's old "Windows Mobile" operating system. And Microsoft has already announced that a major update, code-named Mango, will arrive sometime in the fall.
Will Windows Phone 7, or Mango, pose a big challenge to today's market leaders? Though skeptics are easy to find, two market analysts recently predicted that Microsoft's smartphones would outpace Apple's in global sales by 2015.
But enough about the smartphone market, which it's worth remembering was once led by BlackBerry and Palm. What does Windows Phone 7 offer, and how does it compare? To get some answers, I recently borrowed an AT&T Samsung Focus from Microsoft. Here's a look at some key aspects of how it measures up:
Availability. Like Android but in contrast to iPhone, Windows Phone 7 isn't limited to one manufacturer or certain carriers. Every major carrier offers at least one version of Windows 7 Phone, made by Samsung, HTC, Dell, or LG. When Mango comes out, Nokia plans to drop its Symbian smartphone platform in favor of Windows.
Prices vary, but incentives are more likely as Microsoft tries to compete with Android and iPhone. AT&T currently offers the Samsung Focus for $50 with a two-year contract vs. $200 for a 16-gig iPhone 4 or high-end Android.
Look and feel. Apple's iPhone is all icons, all the time. Android offers icons, widgets, and endless customization, which helps explain its special appeal to techies. Windows Phone 7's response is "Live Tiles," colorful squares or rectangles with an icon in the middle.
"The concept is 'glance and go,' " says Microsoft's Jeff Morris. Any app you use a lot - or a contact, song, website, or photo - can be pinned to the home screen as a live tile. Their size means that only about eight are visible without scrolling, a drawback to some but appealing to those with tired or aging eyes.
App availability. In this, Microsoft is struggling to get traction against Apple, whose iTunes store claims about 425,000 iPhone apps, or Google, whose Android Marketplace offers 200,000 apps. Microsoft houses its app marketplace on its Zune music-player platform, where Morris says the app count tops 20,000.
"They pretty much have the ones that you need," says PC Magazine's Ulanoff. Browsing the marketplace - all you need is a free Windows Live ID - is an impressive experience for a newbie, with choices in a wide range of categories.
Still, refugees from iPhone or Android may face some frustration. Maura Quinn of Manayunk, a fourth-year medical student at Temple, switched from an older iPhone and was disappointed to learn that she couldn't find Pandora, the Internet radio app, or Epocrates, a popular health-care app.
On the plus side, Morris says Microsoft requires all apps to be installed via its Marketplace to protect them from malware, which has recently plagued Android.
Camera. You don't need to tap an icon to take a picture - just push a button on the phone's side. Anyone who's missed a photo fumbling for an iPhone icon will understand the appeal of that feature.
Microsoft integration. This is a sweet spot for Windows Phone 7, which Morris calls "a first-class citizen for all Microsoft online programs." Microsoft hopes the phone's easy access to its cloud-based business and gaming software, for instance, will boost its appeal.
Will Microsoft make a serious run at iPhone or Android, despite a notable string of failures in the consumer market? It certainly hasn't given up.
"The market is still really wide open," Ulanoff says. "There is plenty of room for competition."
Contact columnist Jeff Gelles at 215-854-2776 or firstname.lastname@example.org.