Other than what you've listed we use Google Hangouts.
I have used hoot http://onhoot.com it works well for streaming mobile first
Starleaf works surprisingly good
appear.in
Google hangouts
Biba
UberConference
I like uberconference a lot, but I had a lot of trouble doing screen sharing while in Italy. This may depend on your internet connection and your global location. The voice over internet was great thou