Compute Instances backup/restore approach

[gcloudLearning]

What is the best approach to schedule  Monthly/ondemand VM instances backup for multiple Vms  in GCP organization .

I came across two methods -

Machine Image 

Backup and DR service

Please let me know out of these 2 what will be more suitable in production env and what is the draw back or limitations with each. I mean which will be easy for backup and restore (when required).

as per this article , they have mentioned that backup and DR is not much mature .https://medium.com/google-cloud/schedule-machine-images-backup-and-dr-solution-for-google-compute-vm...