Microsoft extended me an invitation to the Office 365 beta, and I've spent the last few days checking it out. The good news for prospective Microsoft cloud partners is that Office 365 seems to do a good job of integrating the next-generation Exchange 2010, SharePoint 2010 and Lync features into the familiar BPOS cloud model. For Windows shops -- organizations running Windows XP, Windows 7, etc. -- I can see where Office 365 fits into the picture. But for cross-platform organizations -- running Mac OS X, Google Chrome, etc. -- I see some limitations with the beta I tested.

At a reviewer's workshop I recently attended before receiving my beta account, Microsoft Online Services Director John Betz was on hand to demonstrate Office 365 and answer questions. When someone inquired as to how useful it would be for users of Apple OS X or other non-Microsoft operating systems, since much of the software it integrates with is exclusive to the Windows platform, Betz reassured attendees that such user-case scenarios would be fine.

As a habitual Apple OS X user, I beg to differ. And the fact that it doesn't highlights a major problem with the Office 365 approach. From my browser -- which warned me that I may have a suboptimal experience, even though I'm running the latest stable build of Google Chrome -- I was able to access the Outlook Web App, my SharePoint 2010 Online demo team site, and links to create users and install software.

After a lot of searching for the touted in-browser document creation and editing, I found that (unless I'm missing something major) I couldn't create a document in the SharePoint Online site. What I could do was upload a document and edit it. But the focus is clearly on creating documents in Office 2007 and 2010 and using Office 365 as a middleman.

Eventually, I loaded up Windows XP on my MacBook Pro for the first time in a long time to see what I could see. Yes, saving documents from the included Office Professional Plus to SharePoint works. And while I didn't have anyone to try Microsoft Lync teleconferencing with, the client seemed slick, and Betz's demo, while staged, certainly demonstrated the potential.

But the fact that I needed legacy, Microsoft-centric, on-premise software (Windows XP) to use what's being billed as the ultimate corporate SaaS productivity solution to its fullest extent left a bad taste in my mouth. For contrast, look at Google Cloud Connect for Microsoft Office: it looks at legacy software as an on-ramp to the cloud, not as a key component of the offering.

I have to make one thing clear: TalkinCloud's  is kind of a Guerrilla operation in the channel media landscape... I had no Exchange mailbox to migrate, no BlackBerry to set up, and no users to provision, though the tools were all in place. So it's entirely possible that there are key attractors I'm just missing in my limited experience.

But my final word, based on these first impressions, is that while there's no single thing wrong with Microsoft Office 365, it's more of a hosted service for Windows users rather than a platform-agnostic SaaS offering.

Of course, I have to give Microsoft the benefit of the doubt. I tested an Office 365 limited beta. Microsoft is rolling out a broader beta today (April 18, 2011). We'll be watching and listening closely for channel reaction.

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