Microsoft's Windows 8 dominated countless headlines in the weeks leading up to its launch late last month, but October saw the debut of another major operating system as well.

Canonical's Ubuntu 12.10 "Quantal Quetzal" arrived a week ahead of its competitor, in fact, accompanied by a challenge: "Avoid the pain of Windows 8." That slogan appeared on the Ubuntu home page for the first few hours after the OS's official launch, and attracted considerable attention.

Apparently Canonical decided to tone down its message later in the day—the slogan now reads "Your wish is our command"—but it seems fair to say that the underlying challenge remains.

Ubuntu comes with a variety of software packages, including Firefox, Thunderbird, and the full-featured productivity suite LibreOffice.

Window of opportunity

Ubuntu is a widely popular open-source Linux distribution with eight years of maturity under its belt, and more than 20 million users. Of the roughly 5 percent of desktop OSs accounted for by Linux, at least one survey suggests that about half are Ubuntu. (Windows, meanwhile, accounts for about 84 percent.)

The timing of this latest Ubuntu release couldn't be better for Windows users faced with the paradigm-busting Windows 8 and the big decision of whether to take the plunge.

Initial uptake of Windows 8 has been unenthusiastic, according to reports, and a full 80 percent of businesses will never adopt it, Gartner predicts. As a result, Microsoft's big gamble may be desktop Linux's big opportunity.

So, now that Canonical has thrown down the gauntlet, let's take a closer look at Ubuntu 12.10 to see how it compares with Windows 8 from a business user's perspective.

Perhaps the biggest surprise for many users of Windows 8's mobile-style Modern UI is that it has no Start button.

1. Unity vs. Modern UI

Both Microsoft and Canonical have received considerable flak for the default user interfaces in their respective OSs. In Microsoft's case, of course, it's the Modern UI, formerly known as Metro; in Canonical's case, it's Unity. Both are designed with touchscreens in mind, and borrow heavily from the mobile world.

By removing the Start button and overhauling the way users interact with the operating system, Windows 8's Modern interface poses a considerable challenge for users, who face a significant learning curve.

Unity, on the other hand, became a default part of Ubuntu back in April 2011 with Ubuntu 11.04 “Natty Narwhal.” It has definitely undergone growing pains, but more than a year has passed, and Canonical has revised the interface accordingly. Although it still has numerous critics, most people concede that it has matured and improved. Some observers, in fact, have even suggested that it may feel more familiar to many longtime Windows users than does Windows 8.

One advantage of Ubuntu Linux is that it supports multiple workspaces.

2. Customizability

Linux has long been known for its virtually limitless customizability, but given the current controversy surrounding desktop interfaces, that feature has become more salient than ever.

This is a point on which Windows 8 and Ubuntu differ considerably. Yes, Windows 8 does allow users to customize some aspects of their environment, such as by specifying the size of Live Tile icons, moving commonly used tiles to the left side of the screen, or grouping tiles by program type.

Most of the changes you can make in Windows 8, however, are largely cosmetic, and they don't include a built-in way to set the OS to boot to the traditional Windows desktop. A growing assortment of third-party utilities such as Pokki can restore that capability, but otherwise you're stuck with Modern UI. Windows 8 offers what you might call a "tightly coupled" interface—in other words, one that you can't change substantially.

Microsoft's Windows Store was sparsely populated at launch, but company executives have said that the number of apps will increase quickly.

Ubuntu's Unity, in contrast, is more of a loosely coupled UI. First and foremost, you can easily replace it with any one of several free alternatives, including KDE, Xfce, LXDE, GNOME 3 Shell, Cinnamon, and MATE.

Also available for Unity are third-party customization tools, including the increasingly popular Ubuntu Tweak, while a raft of “look” sites are available for myriad Linux interfaces with a variety of themes to change the desktop's appearance.

The rule of thumb with Linux in general and Ubuntu in particular is, if you don't like it, swap in something else. Also worth mentioning is the fact that Ubuntu supports multiple workspaces, essentially letting you run up to four different desktops; Windows 8 Pro does not.

3. Apps

Whereas Windows 8 Pro comes bundled with Microsoft's Internet Explorer 10 browser, Ubuntu comes with a wide assortment of open-source software packages such as Firefox, Thunderbird, LibreOffice, and more, offering both individual and business users a pretty full suite of functionality.

Similar to Microsoft's SkyDrive, Ubuntu One allows users to back up and access their files from Ubuntu, Windows, the Web, or a mobile device.

Beyond those bundled programs, both Ubuntu and Windows 8 offer app stores to help users find the additional software they need.

Dating back to 2009, the Ubuntu Software Center now houses more than 40,000 apps, ranging from games to productivity tools to educational resources. In addition, by using Wine or CodeWeaver's CrossOver, you can run Windows programs on top of Linux.

The Windows Store just launched with Windows 8, and at the time of its debut it included just over 9000 apps. Microsoft execs have said that they hope to provide 100,000 apps in the Windows Store within 90 days of the Windows launch.

Operating system binaries and drivers, however, will not come from the Windows Store. Rather, it will have both Windows RT (ARM) apps and Windows desktop (“legacy”) apps. Entries for legacy desktop apps in the Windows Store will take users to separate sites where they can purchase or download the apps. Ubuntu’s repository, on the other hand, centrally stores all operating system and app binaries and drivers.

As a result, aside from numbers, a key difference between the two app stores involves security. Ubuntu provides a GNU Privacy Guard (GnuPG) keyring-protected repository system wherein each application and driver has a unique keyring identity to verify its authenticity and integrity as having come only from the Ubuntu repo system. The keyring method of protection has been highly effective at ensuring that no rogue applications find their way into the repo—or onto users' PCs.

Historically, Microsoft Windows has lacked such a keyring-protected repository. Although Microsoft does support its OS with monthly Windows Updates, no comparable third-party vendor support for updates exists. Because of this situation, users have had to venture online to obtain their own third-party-supported updates manually at separate websites. The Windows Store was developed to mitigate that risk and is specifically designed to curate apps, screen apps, and provide the capability to purchase apps. Time will tell how well it succeeds.