A large part seems to be about the invite feature and UI, which is something that I never encountered because I wouldn't even think about inviting people from inside a video conference software. Passing links around in other channels seems far more useful to me, and is the only way I access or share meetings. And Skype, where you first have to find the people you want to talk with is much, much more annoying there than just sending or receiving a link via an established channel like email. Of course there are many different use cases, and mine isn't necessarily representative.

But in general the most important part of the user experience for video conferencing is the amount of errors or bad connections that happen. For example, I recently use Microsoft Teams, one person was sharing the screen to present something, and for some people the shared screen simply froze and didn't update anymore. That kind of thing is seriously annoying.

The UI doesn't seem too important to me in this case because I almost never use any of it. After connecting in general the only button I use are mute and share screen. Doesn't mean the UI can't be significantly improved, but for me it isn't the most important part of the experience for a video conferencing tool.