I run a conference business. Hopin is the best. We've demo'd everything from Run the World to Brella's new virtual feature to Crowdcast and all the legacy players.

With hopin you get:
- Mainstage streaming keynote, panel, roundtable presentations and discussions
- Face-to-face video networking and meeting opportunities
- Easy break-out virtual group session offerings
- Workshop and education session room area
- Engaging live chat and poll interactions
- Interactive virtual expo booths to learn more about companies and products
- Private virtual backstage/green room for speakers

Crowdcast.io, Run The World, and Hopin have all been easy to use and get the job done

Microsoft Teams Live Events are seamlessly integrated into the Teams experience and growing in capabilities fast.

I would strongly recommend Airmeet (https://www.airmeet.com/) we as a community have tried this to do online events and it just works and gives you desired outcomes.

I recently used Airmeet for attending a virtual event, and it has a fresh new format which mimics a real world conference/meetup. Attendees can join different tables (upto 4 people) and start a video conversation. You can jump in and out a conversations as you wish. It tries to capture the serendipity and variety of real world events, and makes the event more fun than a regular video conference.

The video quality is good, the UI is a bit rough around the edges (it is a pretty new product). But worth a try if you are hosting an online event.