The ease of use, ability to track activity in one place, its many integrations, and it's simplicity as a platform for multiple teams.
There are some things I dislike about this software - lack of flexibility/customization, inability to integrate with other internal applications (e.g., SharePoint), lack of API functionality or easy integration with third party apps like Google Drive, etc. It does not have a lot of customization options outside from what Microsoft provides - more customization would be great! We solve problems around tracking team members' activities within our organization, so we're able to see who hasn't been active lately vs people who are always actively engaged.