What Is the Microsoft Office Enterprise Edition?by Aaron Parson
Unlike the business editions of Office 365, Office 365's enterprise subscriptions have no limit on the number of users, so medium and large companies can deploy Office to as many employees as necessary. In addition to the regular Office applications, enterprise copies of Office 365 include remote administration, 24-hour phone support and synchronization with your company's existing user directory.
Microsoft offers four tiers of Office 365 for enterprise: E1, ProPlus, E3 and E4. Enterprise E1 is comparable to Office 365 Business Essentials in that it includes several online components -- company email and video conferencing -- but you can use only the Web-based versions of the Office applications. ProPlus works more like a traditional installation, providing desktop copies of Office but lacking the online extras of E1. E3 combines both plans, offering desktop programs and the extras from E1. E3 also includes additional features related to maintaining legal compliance and preventing data loss. E4 contains all the features of E3, plus Lync Server for replacing or extending your company's phone system.
Subscriptions and Updates
Each enterprise tier has a different per-user cost. As of the date of publication, E1 costs $8 per month, ProPlus $12 per month, E3 $20 per month and E4 $22 per month. All subscriptions require a year-long contract. Unlike traditional Office licenses, Office 365 subscriptions include updates, so there's no extra cost when Microsoft releases a new edition. Also unlike traditional licenses, however, you have to pay for Office 365 as long as you want to use the software. If you end a subscription, you lose access to all Office programs.