This is a post that I decided to write after listening to a few customers that obviously got the wrong end of the stick in terms of information about Office365. It seems there is some confusion out there so let me try to “clear the fog” …
Office365 is comprised of Exchange Online, SharePoint Online, Lync Online and Yammer (depending on the plan you have). Also, depending on the plan you will get the “Office WebApps” as well as Office 365 Pro Plus. There are also available add-ons that supply things like CRM Online (amongst other things). Aside from Yammer, which has always been an online service, all of the products mentioned have on-premise equivalents such as Exchange 2013 in place of Exchange Online. So, from that point of view, there is nothing in O365 that you can’t have on-premise.
The big differentiator is in the “scope” of what you get in O365 versus on-premise. First and foremost, O365 is a continually evolving and changing thing; the underlying technologies are constantly being updated with Microsoft now moving towards weekly updates and improvements to O365. This means new features will be added in to the component pieces within O365 much sooner than they will be made available to on-premise installations via standard patching and update mechanisms. There is even the possibility that there will be features only available within O365 although I don’t believe that has happened to this point in time. This is all due to the cadence of updates that Microsoft now follows as part of their “Cloud First” strategy.
Secondly, O365 generally offers access to “Enterprise” product features in Exchange, SharePoint and Lync (depending on your subscription level) that most on-premise installations lack due to the cost of licensing those features (or of the cost of the needed supporting infrastructure). It’s not that you couldn’t have the features, it’s just that you might not have been able to afford them. O365 gives access to these features at very attractive price points which makes it much easier for organizations of all sizes to access and leverage those features.
So, going back to my original statement; no, there is nothing that O365 offers that you can’t have on-premise. The question really comes down to what is the better way for your organization to access all of the features offered by the component products that make up O365? For most organizations the “entry cost” for access to the full feature set is significantly less going with O365 vs on-premise. The on-going cost is also generally much lower as there is far less maintenance involved with O5365 than with on-premise. The choice, ultimately, is yours but I believe with all things being equal that O365 has the much more compelling argument.