The literature for joomunity and jomsocial primarily indicate that they are similar to Facebook.

JomSocial advertises that you can have groups, private messaging, buddies, private albums, and support for third party applications. Cool. $150 to do what Facebook does for free except not quite as well and without the existing user base. Joomunity is pretty much the same stuff but, apparently, none of it even works yet because it is Beta.

All that I would really like to see is a nice user-friendly and pretty way for CB users to post links to their other social networking sites in their profiles. And I think the CB outlook on that is "fine...go develop it." So please-someone develop it. I'll pay $25 for it.

Anyway--I would not dare to switch community extensions until Joomla 1.6 comes out. The things they're talking about having in there - user groups - are going to be really make-or-break for all these guys because that will probably be a massive change to the core.