Windows 8 may be the biggest gamble in technology history. Instead of simply updating Windows 7 with new eye candy and features, Microsoft chose to build something completely new—a combination tablet/desktop operating system. The company's line is that it's a "no-compromise" proposition—a touch-friendly environment for tablets combined with the ability to run all your existing Windows programs. I've been using and writing about the operating system in both its pre-release versions and the RTM (released to manufacturing) version for over a year now. I consider the new hybrid tablet/PC operating system compelling, beautifully designed, well-thought-out, and fast. And its upgrade price of $39.99 for users of all Windows versions back to XP represents a new level of value from Microsoft.

But there's a learning curve, and one that has and will exasperate many first-time Windows 8 users.

Users of Windows versions from the last dozen years or more will be greeted with something completely unfamiliar: The newfangled Windows Start screen, featuring Windows-Phone like tiles that display info based on the apps they represent. Touching or clicking on a tile, as you'd expect, opens the app, but it's after this that the perplexity sets in. To really get going with the OS, you need to know a few gestures, either mouse or touch. This contrasts with using an iPad, which most people could pick up and use without needing to know about any special actions.

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Still, I'd argue that the learning curve for using Windows 8 is not as steep as a lot of articles would have you believe, once you have these few tips under your hat. Much has also been made of the OS's slant toward touch input, and it's true that Windows 8 makes interacting with your finger on the screen a fully functional, smooth option. After a couple days' use, I found navigating the OS nearly as fluid using mouse and keyboard, though some actions remain awkward.

To bring back a large measure of the comfort factor to longtime Windows users, one of the Start screen's tiles, Desktop, returns them to a warm and fuzzy land—a Windows Desktop. This desktop "app" not only looks pretty much identical to the familiar Window 7 interface, but in fact lets you run any program you could run in Windows 7.

A Tale of Two OSes
This duality between new-style (formerly known as Metro) interface and apps and the traditional desktop environment is just one to be found in the new operating system. Another is between Windows 8 and Windows RT, the latter of which will only run the new style apps and desktop apps specifically updated for it (such as Microsoft Office). RT is designed for devices, usually tablets, such as Microsoft's own Surface RT, centered on mobile processors using ARM designs. These make for lighter, longer-battery life tablets. But there are serious limitations with Windows RT, which you can read about in 6 Things You Should Know About Windows RT.

This two-in-one operating system is a radical departure from competitor Apple's approach. The Mac and iPad maker brings its phone OS up to the tablet as a completely separate entity from its computer OS. Microsoft, by contrast, wants to bring the full capabilities of its desktop OS to the tablet. Microsoft has often used the phrase "no compromises," meaning you get the best of both worlds, but a lot of desktop users may feel that their Windows 8 interface is compromised in favor of touch tablets.

A further breakdown of Windows 8 (not RT) is between its two main flavors—Windows 8 and Windows 8 Pro. A much simpler choice than we've had with past Windows releases' edition overload. Pro adds some corporate support (joining network domains and the like) and support for Windows Media Center. This review is based on Windows 8 Pro running on an Intel-based Samsung tablet and on laptops running the same.

Windows 8 brings more than just an interface and app-running capability. It's also a set of services, courtesy of the new Microsoft Account (which any Hotmail, Xbox, Messenger, or Outlook.com account can supply) and SkyDrive. When you log in to any Windows 8 PC, your settings, (new-style) apps, email account, color-theme choice, and more will be replicated. This eases setup when you get a new PC. You'll also get online storage and file syncing that can be used by apps as though it were local storage. Apps and sites can also take advantage of single-sign on, thanks to the Microsoft ID login, saving you from repetitive account setups.

The Windows Store, where you acquire new-style apps, will use your Microsoft ID to keep track of your downloads and purchases, which, as with Apple's Mac App Store, you can install on any other computers after logging in. The Store also keeps track of which apps need updating. It will list pages for old-style desktop apps, but those must be installed on the desktop and don't get the update and multi-install features.

Before delving into a detailed analysis of Windows 8's interface and features, let's take a moment to enumerate what the new OS offers upgraders:

• Much faster startup time, and improved overall performance.
• New Start screen with live tiles that update with app info such as arriving emails, news items, weather, and stock tickers. Default apps are included that provide all this.
• Syncing with all your PCs through Microsoft account sign in. This capability syncs personalization preferences, Internet Explorer favorites, backgrounds, WiFi passwords and more with cloud-connected accounts.
• New App Store. The apps sold here will run on both Windows 8 tablets and full PCs. The apps will have to pass standards, and can be updated and installed on multiple PCs in your account (just as with the Mac App Store). They'll also get the ability to connect with other apps for services like email or social network updating.
• SkyDrive cloud storage that any new-style apps can use.
• Improved battery life for laptops as well as tablets.
• File History—automated backup and versioning utility.
• Faster Wi-Fi reconnect times.
• A much improved browser, Internet Explorer 10, with far better support for the new HTML5 standards and faster performance.
• New Task Manager and more informative file-moving dialogs.
• Trusted Boot. This prevents malware from loading before the OS, on systems with UEFI boot. In general, security in Windows 8 is much tighter than in Windows 7 (though we've heard that song before).
• Built in Consumer apps—People, for social network contacts; Photos, Mail, Messaging, Calendar, and Video.
• Xbox Music—a free streaming music service similar to Spotify.
• Storage Spaces—Lets you easily use multiple drives as one large virtual pool of storage.
• ISO mounting. The OS can now make a disc image file appear as a drive.

You'll get all this and more for a mere $39.99 upgrade from Windows XP and later. And don't forget that Windows 8 runs on any hardware that can runs Windows 7. It will also be able to run any programs that run under Windows 7, unless you opt for a Windows RT tablet, which will only run (some) new-style Windows 8 apps.