Topic: Help required on

I want to add a virtual classroom section for my website. The website will have multiple apps running , most of which will be RoR based.

I did find some APIs for online conference{tokbox , smiletiger and mikogo} but i am not sure about their reliability. Please suggest a viable option

The following are my requirements :-
  1. Basic video conferencing capability among >= 20 participants
  2. Ability to share documents , spreadsheets and presentations
  3. Ability to view the desktop screen of a particular participant
  4. Reliable in use