Disclaimer: current/new Cisco employee, though I don't work anywhere near Webex.
Webex is... amusing, from an internal perspective. Partially because of the namespace collisions: Webex Teams, Webex Meetings, or Webex Trainings? I've run into all three, and all three are different.
As far as I can tell, Teams is supposed to be our Slack-adjacent/competitor. It works... fine. My previous corp had switched from Flowdock to Microsoft Teams, and M-Teams was truly, truly awful as a chat client. At least W-Teams behaves how I would expect a chat client to. (Though I dearly miss the full emoji reaction selection.) The media viewing behavior, or the group creation behavior (I can't just make an ad-hoc group chat between people, I have to create a 'space'--Why?!)
Webex Meetings seeeeeemmmsss to be just the realtime video component? The Zoom-adjacent/competitor? Teams integrates this on its own, so it's hard to tell sometimes. Broadly I think the Webex UI for calls looks/feels/behaves better than the Zoom equiv, and I have felt that the AV/screenshare quality is notably better than Zoom or Hangouts. But on Zoom I'd always bumble through the menus, or feel like I had a zillion buttons in front of me and didn't know what they did, or be annoyed with how to even create a meeting. (This last one is really counfounded for me, 'cuz the calls are integrated into Teams, so I never have to leave the chat client to make a call, which is likely not the case for other Webex users.)
Webex Training is... Hillariously frustrating. It feels like it hasn't been updated since inception (which looks like it was 2004). There are so many terrible, terrible UX decisions that the Cisco meeting facillitators call out every time they run up against. ("We're going to play a video, so everyone make sure you've muted yourself so the audio doesn't leak and that your laptop speakers are on so you can hear the video," or "We're going to forcibly unmute all of you so you can have control over your own mute/unmute <unintelligble hash of insane noise from all participants>", the mute/unmute/reaction buttons being impossible to find and CHANGING POSITION DEPENDING ON ROOM AUGH)
Anyway. Point is, I've felt similarly to the above, but only within specific Webex domains. I've really been meaning to find a Webex engineer to sit down and ask why this stuff hasn't been fixed, but I suspect I already know and the answer is the same as at my previous corp: Maintenance was de-prioritized, and now minor issues have become egregious, but it would require massive engineering effort to even begin solving them.... and those resources would be better spent on $Successor to get it fully up to spec to replace the aging/ailing incumbent. Meanwhile, the "modern" versions of Webex (Teams, Meetings?) seem to work well enough within the corporate boundaries that we don't feel the pressure. Doubly so because Cisco employees don't get the opportunity to see what life is like "on the other side of the fence" with Zoom/Slack/Flowdock/whatever--which, yay, dogfooding, but boo, lack of contrast.