If what they sell is the open source Nextcloud, it is a horrendous product.
Its architecture is weird, with a proxy inside you can harden only by editing data inside a container that is volatyile by design (and has to be).
There are numerous issues opened on that topic, Nextcloud response is "live with it".
We use it at work and everybody I asked loves it. I also recently moved my personal data to Nextcloud from Google Drive and it's been extremely pleasant to use
Its architecture is weird, with a proxy inside you can harden only by editing data inside a container that is volatyile by design (and has to be). There are numerous issues opened on that topic, Nextcloud response is "live with it".