Microsoft debuted Office 365 today, taking on Google Apps for Business. (TOBIAS SCHWARZ/REUTERS)

The suite includes Word, Excel, PowerPoint, OneNote, Outlook and Lync, as well as other services depending on which package you choose. All packages have collaboration tools and online and offline syncing. Documents can be accessed through a desktop or mobile browser, and you can instant message and video chat, though there’s no telephone integration.

Plans for professionals and small businesses cost $6 per user, per month. For larger companies, the company has plans ranging from $10 to $27 per user, per month.

On Monday, Shan Sinha, a product manager for the suite’s main competitor, Google Apps, panned the new product on the Google’s Enterprise blog. Sinha said that, compared to Google Apps, Office 365 is antiquated, closed and costly.

“Before you invest ten years in the past, we’d humbly encourage you to invest ten minutes in today by checking out why so many businesses have chosen Google Apps,” Sinha said.

In the post, Sinha criticized Office 365 for its tiered pricing — Google offers its professional Apps service for $5 per month — and said that it is too tied to the PC, pointing out Google Apps work on any operating system and require no software.

For many businesses concerned about storing all their files on the Web, however, the fact that Office 365 lets users work online and offline may be a major selling point. And Microsoft has taken pains to court those companies not quite ready to make the full leap into the cloud by making its Web apps just about identical to Office, down to the formatting and the user interface.

Microsoft is banking on that familiarity to coax its users into using its new service. By working with the programs already running in millions of offices worldwise — Outlook, Office, etc. — it can market Office 365 as a way to ease into cloud computing instead of jumping.

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