Selfhosted

I started and ended up bailing. The deciding factor for me was the way data is stored with OCIS (basically hashes), so backup/restore would be a much larger pain. So I'm sticking with Nextcloud as much as I hate PHP and dislike the performance issues.

I had good and bad times with both. I am finally happy with "pydio cells"

Not really what you are asking for, but I found the combination of KaraDAV and Filestash to be a great alternative to Nextcloud, and much more stable for basic use.

As for Owncloud... I am skeptical of the company behind them ever since they split off into them and Nextcloud. Probably better to avoid, regardless of what you think of Nextcloud.

Nextcloud Docker compose https://hub.docker.com/_/nextcloud/

I don't do much maintenance on my nextcloud image either. I spend a lot of time setting it up on bare metal because I didn't know docker compose existed but it's very popular nowadays. With docker compose you don't have to setup a lot either. It didn't break for me once in the past years.

What's wrong with nextcloud's S3 object storage?

Assuming you just want file sync and storage, if you can live without External Storage (having another SFTP/WebDAV/whatever backend), then I think oCIS is great for you. It also expect an OIDC auth provider by default - this guide helped me through. Note that you have to configure the S3 storage driver in oCIS and properly backup your buckets and metadata.

For Talk you can setup an internal Matrix and TURN server too. I recommend conduwuit if you want something lightweight, or Synapse (quite heavy) if you need OIDC integration.

No idea at all, but I am highly interested in your experience. So it would be great if you could came here back to share it with us

I am considering switching as well, for similar reasons. What has been holding me back (besides missing time to plan and do the migration) is thst I don't quite trust ownCloud any more, and due to a lack of documentation, I would want to run it in parallel for some time to get the hang of it before migrating the other users (which adds to the time constraint).

I'll most likely deploy using their helm chart – does anyone have any real-world experience with it?

For what it's worth, I do think OCIS is worthy of switching to if you don't make use of all of the various apps Nextcloud can do. OCIS can hook into an online office provider, but doesn't do much more than just the cloud storage as of right now.

That said, the cloud storage and UX performance is night and day between Nextcloud/Owncloud and OCIS. If you're using a S3 provider as a storage backend, then you only need to ensure backups for the S3 objects and the small metadata volume the OCIS container needs in order to ensure file integrity.

Another thing to note about OCIS: it provides no at-rest encryption module unlike Nextcloud. If that's important to your use case, either stick with Nextcloud or you will need to figure out how to roll your own.

I know that OCIS does intend to bring more features into the stack eventually (CalDAV, CardDAV, etc.). As it stands currently though, OCIS isn't a behemoth that Nextcloud/Owncloud are, and the architecture, maintenance is more straightforward overall.

As for open-source: OCIS released and has still remained under Apache 2.0 for its entire lifespan thus far. If you don't trust Owncloud over the drama that created Nextcloud, then I guess remain wary? Otherwise OCIS looks fine to use.

If I wasn't using so many other Nextcloud apps besides the file storage I would switch.