[boulos]

Not bad! Can I recommend that you try out the per-object storage classes and lifecycle policies? Particularly if folks are going to be effectively rsyncing things, it's really handy to minimize the combination of retrieval fees and storage fees (this really depends on the manner of backup, incremental versus full, etc.).

Also not mentioned is that each service also supports versioning, which for backups that don't do block-based backup, can be an alternative DR plan (e.g., don't allow some users to delete the last version).

All in all, a good start (complete with helpful screenshots!). Looking forward to the guides on S3 and Azure Blobs.

Disclosure: I work on Google Cloud.