Microsoft Office 365 Enterprise E3 is a fantastic product. Easy to use, and very easy to manage both via the admin portal and PowerShell. I have used this both as an internal IT professional, and working for an MSP to set up, migrate, and manage a number of clients, and have not had many problems at all. I'm very happy with the product, and would recommend it as a solution. Though, the price could be tonned down, looking at you microsoft, only thing that made it buyable was My Choice Software discount.