I have used the Boonex Dolphin social networking script. You need to have a good host who is familiar with Boonex as there are heavy demands on the
server due to video chatting, uploading and downloading videos and instant messaging. It's free to download and try out - I have it on my Cpanel via
Softaculous.
Yes community builder is pretty good you can set up comment walls (facebook style), groups, user galleys etc etc. I've found it to be pretty
processor hungry server side though