The verdict
For a small team whose only goal is to hand sales a short list of engaged people after each webinar, pick Demio. The focus level score and the poll and handout tracking are the reason it exists, and the setup is quick.
If you run webinars on a regular schedule, want a free plan to test the room, care where attendee data is stored, or plan to automate around the API or MCP server, pick Livestorm. Its pricing follows audience size, not team size, so a bigger team does not raise the bill.
For most small B2B teams I'd pick Livestorm. You can try it for real before paying, and the EU hosting answers a question that buyers ask. Demio wins only when the engagement score is what you will actually act on.