I use it day in, day out. My 'provided' work device is a Thinkpad running Ubuntu, so any local work is on Libreoffice. Same when working from home on my personal devices (a mixture of Mint and Ubuntu) - Libreoffice does probably 98% of what is needed; it's only pre-written stuff that my employer supplies with MS-specific macros that give me any bother.
If I need to get something into a 'real' Excel format (for example), then I'll just load the Libreoffice output into our workplace Office 365 online subscription and export back out... but more often than not the .xlsx / .docx / .pptx output is more than fine.
I'd say office productivity work is probably no more than 20-25% of my output; the rest being technical documentation (usually markdown format), code or lifecycle management stuff (e.g. code releases / acceptance testing / bug reporting - so plain text)... so while I'm not the biggest productivity software user, Libreoffice works just fine in the vast majority of cases.
My collection database and technical wiki:
https://www.target-earth.net