I'm using Nexcloud currently, but an alternative for you to check out for you might be Pydio.
It has a lot of the same features, and generally seemed a little more stable. However, it was a little more painful to configure, and has a few unique terminologies you'll have to get used to. Also it's UI does load faster than Nextcloud, but once loaded, it is a little less snappy.
For the user downloaded client, I found that it works, but is a little less convenient than Nextcloud (no Automatic pinning of the folder, no partial downloads to save space)
It has a lot of the same features, and generally seemed a little more stable. However, it was a little more painful to configure, and has a few unique terminologies you'll have to get used to. Also it's UI does load faster than Nextcloud, but once loaded, it is a little less snappy.
For the user downloaded client, I found that it works, but is a little less convenient than Nextcloud (no Automatic pinning of the folder, no partial downloads to save space)