What it is: Google's new phone OS is an ambitious open-source platform intended to let companies customize it to their liking for an array of handsets. So far, however, it's available on just one model, T-Mobile's G1.
How it works: On the G1, Android's interface feels like an iPhone/BlackBerry mashup--much of it uses the touch screen, but you get a trackball and Menu, Home, and Back buttons, too. The highly customizable desktop is a plus. Overall, it compares well to older platforms but isn't as effortless as the iPhone.
How it looks: Android isn't an aesthetic masterpiece like iPhone OS, but it's fresh and appealing, and it makes good use of the G1's high-resolution screen.
Built-in applications: They're tightly integrated with Google services such as Gmail and Google Calendar--the first thing you do when you turn on the phone for the first time is to give it your Google account info. (That's fine as long as you're not dependent on alternatives such as Microsoft Exchange.)
Android's browser lacks the iPhone's multitouch navigation but is otherwise a close rival. The best thing about its music features is the ability to download DRM-free songs from Amazon. The only videos it can play are YouTube clips, alas.
Third-party stuff: Developers are just beginning to hop on the Android bandwagon. The iPhone-like Market service lets you download apps directly to the phone from Google; unlike with the iPhone, you can also snag programs from third-party merchants such as Handango.
Bottom line: Android's potential is gigantic, especially if it winds up on scads of phones. On the G1, it's a promising work in progress.
RIM BlackBerry OS
How it works: The basic concepts behind the BlackBerry interface have changed remarkably little in a decade. And why should they? In its own way, the BlackBerry interface is just as logical and consistent as the iPhone's: On most models you perform almost every function in every application with a trackball, a Menu button, and a button that lets you back out to the previous screen.
Master those three actions, and you can whip around the OS with extreme speed. (I haven't tried the Storm, which replaces the standard BlackBerry controls with an iPhone-style touch screen.)
How it looks: The BlackBerry OS is fairly mundane and text-centric, although recent models such as the Bold dress it up with crisper fonts and slicker icons.
Built-in applications: The BlackBerry's e-mail and calendaring applications still set the standard for efficient design and reliable real-time connectivity with widely used messaging systems such as Microsoft Exchange.
The Bold introduces a much-improved new browser that rivals iPhone OS and Android in its ability to display sites the way their designers intended; its music and video apps are serviceable enough but still secondary to the productivity tools.
Third-party stuff: Once upon a time, users didn't have many BlackBerry programs to choose from, but recently the market has boomed--thousands, from productivity apps to games, are available now. Windows Mobile and S60 have even more bountiful selections, though.
Currently BlackBerry has no over-the-air storefront comparable to Apple's App Store or Android Market. RIM's BlackBerry storefront is expected to launch in March 2009.
Bottom line: The BlackBerry OS is an old dog, but a smart one--and one that's proving itself capable of learning new tricks.
Next: Microsoft Windows Mobile and Nokia S60 3rd Edition on Symbian