I've been using Nextcloud for several years. I prefer Owncloud but Owncloud, IMO, is pretty arcane. The con for Nextcloud is that it feels heavy and is slow.
Nextcloud is a PITA to maintain via snaps in Ubuntu. Something is always breaking or not working properly and most of those issues tend to be related to snaps.
I decided to try Nextcloud via containers. I am very surprised - it feels light and quick in comparison to installing natively on HDD. The host system has an SSD. I deployed it via Portainer, but I had to butcher someone else's docker compose YML file. The file looks ugly but I've a running system. This is my second attempt at deploying Nextcloud as a container - the first attempt had DB access issues that I was having a difficult time sorting.
Even when importing files (videos, pictures, and music) into Nextcloud, there was less of a system load.
For now, I'll monitor the system while using it with a small subset of data (it currently has 40 GB of files). I don't want to spend the effort of moving a massive amount of files only for the instance to die (I do have persistent volumes enabled for the container, though). The app container is consuming 4 GB of memory, though - that's a bit high, IMO...not sure if it's experiencing a memory leak, as it's using 4 GB while idle.
UPDATE (11/14/2025):
I decided to try to deploy a containerized Owncloud instance. The compose YML file was a bit more beefy. It was copied from the Owncloud documentation.
I had to deploy this one from CLI, for now...I ran into an issue that I need to sort out - once I sort it out, I'll redeploy using Portainer.
I did run into an environment setting issue. OWNCLOUD_TRUSTED_DOMAINS needed an IP value (IP of the server itself) - the documentation is vague on this and I found the answer from within a bug report.
I thought that a containerized Nextcloud instance was quick - this server is even quicker than a containerized Nextcloud instance.
I will have a bake-off of these two instances, but I suspect I'll be again adopting Owncloud as a docker cloud app.
UPDATE (11/17/2025):
One thing that is super weird is that Owncloud won't allow uploading of directories. To upload a directory of MP3s, for example, I've to create a folder named, "MP3s" and then upload all the files within the MP3 directory. WTF?! Note that I can move folders if I use the Owncloud client software. I'm not wanting to install the client software on every system I have. It's like they're actively fighting to not have a directory upload feature. With Nextcloud (and Google Drive, and OneDrive), I just have to select the folder and the whole folder is treated as an object (meaning, the the directory and it's contents will be uploaded/downloaded). It's damned silly not to include it. I think I ran into the same issue years ago when I used Owncloud (like 7+ years ago!). I researched and someone said, well it works with Google...blame the browser creators (double-WTF?!) Nah...I'm blaming Owncloud because things like that are silly and if they're doing things like this, what else are they doing within the code? It looks like Owncloud decided for me which to use (and it's not Owncloud). I'm glad I didn't manually install it, only to see the lack of directory uploading.