To be honest...
After using all of the services listed over the past 2 weeks, they've all had issues to a lesser or greater extent. The most reliable one so far has been Microsoft Teams (It surprised me as well), but that could be that we've got a dedicated enterprise cloud server setup for it (as opposed to the general cloud service for the unwashed masses). Webex has long been known to suffer from issues using a computer for audio and we've used ...HAS JOINED THE MEETING..m since calls work better, as for video that's normally LINE MUTED..less you have a crap home/office broadband.
Also Teams doesn't suffer from Skype for Businesses anBONG!..ng when someone joins the meeting bEfOrE tHiNgS sOuNd LiiiiiiiKe ThEy'Re In A fIsHtAn..............
And don't even get me started on Zoom. Great with a 300mb line, crap with whatever wet piece string others on the conference were using. Especially if they're trying to stream a video over it (only just got the dried blood out of my ears from that one).
On the flip side. Who'd've thought that the dream of video calling from 2001:A space odyssey would happen because of a virus? (Though I still call BS on that scene since the call worked seamlessly and with perfect audio).