Both the open and closed source versions share the following features:

WEB user interface for conf managing (mutes,kick participant..)
SIP based (Sailfin or Mobicents) allowing easy integration with any SIP infrastructure
WebRTC support
VP8 (VP6 on decoding), H264, MP4V-ES H263P, Sorenson H263 and H263 support (on the same conference)
PCMU, PCMA, G722, GSM, SPEEX, NellyMoser, AAC (only encoding) and Opus support
Continuous presence allows view all participants on screen simultaneously
Ad Hoc conference creation based on templates
Audio mixing in 8khz,16Khz,32khz and 48Khz
Conference recording in FLV and MP4 formats
Flash broadcasting of conference
Up to HD720P video size
NAT traversal support: Symmetric media, STUN and ICE lite support
Multiple layouts
VAD positioning
SRTP, SAVPF and DTLS
FEC, NACK and RTX support
Bitrate Adaptation Algorithm

The closed source version has also the following additional features:

Flash participants supported
RTMP publishing of conference in a remote flash server/CDN
RTMP broadcaster
3 way conferences
Web Service API and HTTP REST API for conference management with conference events notification
Integration with an external service for participant authentication
Multiple mosaics per conference allowing to customize the view for each participant
Automatic layouts based on number of participants
Custom mosaic per participant to remove selfview
Multiple audio sidebars per conference allowing to customize the audio heard by each participant
Define max duration and max participants per conference
PNG and SVG overlays and image presentation support
Display participant names on video
RFC 5366 Conference Establishment Using Request-Contained Lists support
RFC 4028 Session Timers support
CDRs
Screen Sharing via VNC over Websockets
Presenter control via BFCP JSON over Websockets
HA & load balancing
Integration with Google Compute Engine APIs for automatic resource management
Customization and support included in license price

Functionality

MCU