I’ve been testing it and it seems like a good solution for general productivity and a great option for people migrating from MS. It’s open source and cross-platform, but I just don’t see it in any conversations about office software.
For me, it’s so far leagues beyond LibreOffice. I really need something that works on my phone and syncs across devices, and allows collaboration. OnlyOffice seems to fit the bill. It’s also far more intuitive to my preferences.
I am sure that some people wouldn’t like the fact that the interface runs as a webapp, or use of Java, but it’s strange to me that it’s not usually even in the conversation.
I use ONLYOFFICE desktop apps on my local computer, and I love it. My niece also uses it, and doesn’t really notice the difference to MS Office. I also have ONLYOFFICE Server running and integrated to Nextcloud so I can, if needed, open/edit files from a browser.
I am aware of the [dubious] complaints that Russians were once involved in its creation (WAY BACK in 2009), and I still don’t care since everything is open source and on Github.
If someone asks a question where ONLYOFFICE can be a solution (recently, a proper PDF editor using open source software) I suggest it.
LibraOffice imo is the most behind of the three options, and Collabora Office works, but it is in no way similar in operation to MS Office making it a difficult sell to your mum/family.
https://en.wikipedia.org/wiki/OnlyOffice
https://github.com/ONLYOFFICE/