Veeam Office 365 Backup is a must have product.

Veeam Backup for Microsoft Office 365 is being used across the organization to backup Office 365 email
/ OneDrive and the company SharePoint online portal. It solves the retention issue for Office 365 mailboxes as well as protects OneDrive and SharePoint files. When employees leave we can remove their Office 365 accounts right away knowing that we have an on premise backup of their files.

When we started migrating users to Office 365 and using SharePoint Online, there were people in the company that were uneasy with not having a copy of data on premise. This solution put everyone's mind at ease. It brought our cloud data into the same retention policy as our on premise data, which significantly reduces our risk of data loss.

Office 365 only keeps mailboxes for 30 days after a license is removed. When an employee leaves it sometimes takes months before its noticed that they purged important emails prior to leaving. We have used Veeam on several occasions to export mail from an ex-employee mailbox for a manager or human resources. Also with the amount of data people keep in mailboxes a deleted folder can sometimes take months to discover. Veeam protects users from themselves.

The flexible options make it easy to move data around between mailboxes or in a hybrid environment like our between on premise exchange and O365. The Veeam explorer view is also a quick and easy way to find missing emails from any point in time.

The PST export is one of my favorites its great for exports and moving data between mailboxes. The simplicity of the setup and exploration of backups makes my job a lot easier.