I just installed it an opened a spreadsheet with a chart, that I made a few years ago and is a good test of compatibility. Some of the labels on the chart weren't displayed correctly. This is a problem with several other Office alternatives too, but not all of them. I believe that some people require functionality that only Outlook provides. I don't, as I don't use any email clients.I completely agree but have you tried OnlyOffice?
Its compatibility with MS Office is amazing.