Here's a video from over 3 years ago doing live editing in Office 365: https://youtu.be/0u-iYJFx78c
Here's a more recent video: https://blogs.office.com/2015/10/30/word-real-time-co-authoring-a-closer-look/
On my Mac, this feature doesn't seem to work as advertised, but I could be doing it wrong.
Even though the automagic sync thing doesn't work, I have on several occasions collaborated on the same Word document or PowerPoint and just had to manually sync changes. So far, not a single issue has been caused by multiple people working on the same file at once.
I think Microsoft Teams was a real game-changer for their collaboration too.
Once again, though, if Google allowed us to use their discount it would be a tough call. Since we don't qualify, we'd have to pay, so no matter how much leadership likes Google it is just too difficult to pass up O365.
For documents we don't print we use OneNote, which does sync very well across devices (Mac, PC, etc.)
I imagine if we were all PC the difference between G-Suite and O365 would be much smaller. I also have noticed more Mac friendly software and more robust web-apps from Microsoft, so most of the features staff want are either already available or on the current roadmap.