[K12OSN] Groupware recommendations?

[Eric Worthy@home]

I have no experience with any of these groupware products but it is 
clear there is LOTS of development going on in serveral fronts.
There are three notable open source projects in various stages of maturity.

Open Groupware and SKYRIX:   whick is linked to and supported by the 
'openoffice' boys

           http://www.opengroupware.org/en/index.html

PHPProjekt: now in release 4.2

           http://www.phprojekt.com/

hipergate: mostly a windows product but as it is java based and can use 
Postgresql has a version that will run on Linux.

           http://www.hipergate.org/about/

Those who may have experience with any of these products are encouraged 
to share.

Eric