Is it? Almost every time I use it I end up hitting a bug or missing feature. Just last week I was trying to get Word in Office365 to keep some lines together. I followed the instructions from Microsoft's help and it didn't work. Last month I was trying to get "slide M of N" on the bottom of PowerPoint in Office365, but apparently getting the N is just not supported.
LibreOffice almost always works for me, far more often than Microsoft Office.
We've already got free software for filing taxes, kthxbye!