I subscribe to Office 365 which, for £80 a year, gives me the full MS Office suite on all home and mobile devices for the family, plus 1TB of OneDrive space. For me, it's worth the cost (especially as I can put it down on my tax return as a business expense) but as always, YMMV.
Apparently, it's free if you have a valid UK academic email address.
Google Docs and Sheets are generally fine in my experience, but I've often run up against their limitations. Having said that, I've also run up against the limitations of the Mac version of Excel on occasion...