I visited a few. The conference day usually starts with getting up early, doing some work with EU clients before going to breakfast. This is doable for a week.
I hope they can stream sessions in future. Apple shows it's possible, e.g. for WWDC '19, where a few sessions were live and others available within an hour after they finished the session.
The panels could have more diversity, especially more women and more Europeans/Asians and not so America centric.
For the first virtual conference, this was great and better than expected. I hope the technicans from Apple can support them on live streaming with HTTP, so we can watch them all on an Apple TV with big screen.
And great was the chat website hosted by Geist interactive. That is something, the Claris Community should include for events. Including all those special virtual rooms. The community itself was rarely used while the conference.
So in future, in-person event with live streaming and video availability quickly, a chat website for all people and we could have much more people active. If 1000+ people come in person and 5000+ people could watch live, we would get a much bigger portion of the 50000 developers engaged.