Skype for Business Meetings provide the ability for up to 250 people to collaborate online by using features such as video, audio, instant messaging, or content sharing.
Skype for Business Multiparty Audio and Video
Skype for Business Online provides multiparty (three or more users) audio and video conferencing capabilities. Active speaker video is available only for multiparty sessions. With Skype for Business Online, users can easily schedule an online meeting with video or seamlessly escalate an IM session to a video call.
The video experience is enhanced by the following features:
For details, you can refer to http://technet.microsoft.com/en-us/library/lync-online-meetings.aspx
Note: Performance will be vary depends on your environment such as network bandwidth.