If you have O365, You must at least try Veeam 365 for you on-premises backups!

Veeam 365 Backup is being used by our company to backup all mailboxes, SharePoint sites and OneDrive accounts. We moved into the cloud back in 2017 and have always felt more comfortable having a copy of our data in-house so this product was just the ticket! We use Veeam Backup and Recovery for our internal VMWare infrastructure and are very happy with the support we get.

We fully researched O365 and understood its limitations from the beginning. We were never going to trust one company to keep our data safe and so we looked into Veeam's offering before moving. There was also a need to keep our backup solution simple. We already had Veeam Backup and Recovery and were able to just add the product to the same server and same repository.

We haven't yet had to deal with any major data losses but we will regularly have to restore files or specific emails for end-users. The process is so quick we always get a happy caller regarding how fast they got their data back.
One Caller had deleted an entire folder from their one-drive account, then deleted their second-stage recycle bin. Because we kept daily backups running for 1 year we were able to get it back pretty quickly once we knew the day it had happened.

We benefit from the ability to export emails to a PST. If a line manager wants to see emails from a staff members mailbox or specific folder in their mailbox, it's often quicker to grab them from Veeam, export to PST and pass the file over.

We also use this to archive data from ex-employees

1. Top notch support
2. Simple Interface
3. Being able to access backup jobs long after their original backup job has gone. Sometimes you need to start a new backup job and remove the old one. Providing you keep the actual data in the repository, you can use the in-built explorers to open these files.