This isn't quite the selling point it once was for a couple reasons. First, even with the desktop Office 2013 suite Microsoft is pushing users to save files to the cloud-based SkyDrive, or to a SharePoint server by default. So, there's no reason the data can't be accessible regardless of whether you choose Office 2013 or Office 365.
The second reason it may not be all that compelling is that Office Web Apps are already available for free from the SkyDrive site. So, even without Office 365 users can create, view, and edit Word, Excel, PowerPoint, and OneNote files from the Web.
For businesses, though, SharePoint, Active Directory, and other elements of Office 365 that go beyond simply creating and editing Office documents still make Office 365 a better value.
Your mileage will vary of course. There are a number of factors involved in calculating the cost of purchasing, installing, configuring, updating, and maintaining Microsoft Office and the accompanying back-end services versus the ongoing subscription costs associated with Office 365. Office 365 is a solid service providing tremendous bang for the buck, though, so it won't be easy to beat the value it brings to the table.
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