It probably goes without saying that nobody supports Microsoft Office formats as well as Microsoft itself does. With the launch of alongside--and integrated into--, Microsoft has effectively filled the void that its earlier desktop apps left open for Google and Zoho.

Microsoft's current Web Apps lineup includes online versions of Word, Excel, and PowerPoint (along with the note-taking app OneNote). All three replicate the look and feel of their corresponding desktop applications, sporting somewhat simplified versions of each app's familiar menus, so making the leap from the desktop to the Web shouldn't induce vertigo in even the most devoted desktop-app fan.

The Web Apps save all of their files to Microsoft's , SkyDrive, where you can set sharing permissions on files, invite people to view and edit your documents, and even collaborate on shared documents simultaneously.

Note, however, that Office Web Apps are not complete versions of their corresponding desktop apps: Microsoft has simplified the features of the free Web apps to ensure that people still buy its expensive desktop suites. In the company's view, these apps are only a Web extension of the programs in its suites, which range from $150 to $500. (Looking for more-comprehensive cloud-based business services? See how .)

Of the three office options here, we prefer Microsoft's offering for its dependable mix of robust desktop programs and work-from-anywhere cloud apps that provide complete, no-hassle support for the most widely used document formats on earth.