Not for a Synology, but I doubt Hetzner cares where the data comes from. Works well, especially once you got the keys in place. Have stored and restored, it's a simple file storage.

I've got the 20TB box for my Jellyfin library. Works great.

I use it with borg from Canada and I've tested it with restic with very few issues. It'll probably be fine for you for mass backup. I have previously tried using it in a more real time situation and that wasn't so great from western Canada.

Storage box networking can be hit and miss. It's ok for incremental uploads, but I went through hell and back to get the initial backup finish, which makes me wonder what it would take to download it in case I have to.

Scp breaks off once in a while, and WebDAV terminates the session. I didn’t try smb as I feel it's a rather weird protocol for the public internet. In the end, I figured it's not the networking per se, it's something with the timeouts on the remote, and I was able to finish the backup using a Hetzner-hosted server as a jumpbox.

But it's cheap, yeah.

A coworker uses it as backup and he is happy about it. I have rented an auction server (a dedicated server) from them and on it is my Nextcloud and stuff and I backup my NAS to my Nextcloud and my Server to my NAS via WebDAV. Zero issues. I had once contact with their technical support, because a Harddrive failed. I was a low priority case but they handled my case exceptionally fast. Opened the ticket on a Friday after a holiday on 23:09 and at 23:51 the hard drive was changed.

What does the price per hour mean?

I use a Hetzner Storage Box as extra storage to my Hetzner VPS. It almost feels like the storage is directly attached. We serve thousands of archives and binaries and have absolutely no problems. It's fast and decently reliable (except some downtime I once experienced). The initial file access time might not be the best but the bandwidth is great.