The verdict
For online webinars and virtual events, and a small B2B team that wants to try before buying, pick Livestorm. You can test the room and the registration flow on the free plan, and you can see roughly what it will cost from your audience size.
If you run hybrid conferences with several tracks, a venue and a need to report across in-person and online guests, pick Webex Events. That is more convincing again if your company already runs on Webex or Cisco.
I'd pick Livestorm for most readers of this site. Webex Events is more platform than a webinar needs, and it comes with a sales process and a quote. Do not buy the bigger tool for the odd online session.