Personally I am a huge fan of NextCloud currently I run 4 environments with over total over 100 users.
Already in the beginnings of OwnCloud I have been working with it and I switched relatively quickly to the fork “NextCloud”. It seems to me that a lot has happened since the fork, the community has grown much bigger. Another advantage is that you have your own DataShareing solution without using commercial products.
I would like to present you my Top 5 solutions, which I use on every NextCloud environment.