In the review, Nicholas Carl Martin wrote about BigBlueButton
It offers the basic features described at the beginning of the post and also employs video conferencing between the presenter and viewers. It lacks recording and mobile integration, but is on a good track and is highly recommended for organizations that have a good handle on tech and want a cost-effective and easy-to-use option.
In regards to the missing parts, the GT-Mconf team working on an android client, and we have record and playback coming in BigBlueButton 0.8-beta.