I don't use these kinds of tools in private unless I have to, and when I do, I found that OnlyOffice has better compatability with .docx-files. I recently had to make some changes and format a .docx-file, and after struggling to make it look correct in LibreOffice*, it did not show up correctly in Word. Output was more or less the same in OnlyOffice as in Word, and after redoing it in OnlyOffice, it looked almost completely correct in Word.

• This is, however, always a problem with these kinds of programs in my opinion.

Libre office was alright but tabbed layout was buggy, entering stuff in excel was delayed by 0.5s everytime, the math formula program required some esoteric knowledge, and libredraw messed up pdfs which foxit otherwise opened with precision. I stick to Microsoft word 2007 which does exactly what I expect.

Between the two I recommend OnlyOffice because it has better export compatibility,, a PDF editor, seamless interchange between their desktop, mobile, and web versions, and a nicer UI. You'd only need LibreOffice if you're doing very advanced document formatting or very niche scientific or financial formulas. LibreOffice has been around for a lot longer than OnlyOffice so its got more edge use cases figured out. Onlyoffice is more modern and IMO feels like a smoother experience with the UI.

There is WPS office (from Kingsoft based in China).