I implemented Owncloud in my workplace, but we had one problem that made us uninstall it and create our own solution in Dart, the problem was that when you share a file it doesn't preserve the file path extructure and that was very important for us.
*structure, becuase every folder has meaning, if they share the document "law_2016.pdf" that is in the folder "/Enterprise_1/documents/laws/info" the folder structure has information about the context of the file in this case, they now is a document of law of the Enterprise 1.