Butter

When I first looked at Butter, I was a little overwhelmed: all colorful, where you're used to a more subdued design from other video tools. At the time, I would have seen it more as an add-on tool to add variety to individual sessions, but not as a foundation for events.
In recent months, Butter has evolved a lot, new options have been integrated, and we now use it to design entire webinars. After some initial irritation, participants really like the "colorful" feel of Butter.