The ability for multiple users or teams in one system is great when you have several people working together as well as different departments within the same business unit (e.g., accounting vs HR).
It's very customizable but sometimes there are issues that arise where certain functions do not work properly. I would recommend trying this software if you're looking at more than just email communication between members of staff - look into using other features such as task management/project tracking etc. We've been able to streamline our processes by being able to communicate better internally across all employees without having them physically meet face to face!