Personally I think GroupJive is pretty great for the most part.
With some GroupJive help, I got it up and running complete with the Forums integration etc, in close to no-time.
Then the upgrade worked great, to Joomla 1.5.10
The thing is as I see it, it does the job nicely, by creating groups, that is private to group Members.
Other functionality stuff seems to be an integration case, which seems to be pretty much under control. At least for my needs...
The only weak point I can really think about is the template side of it.
At the moment, hemi or default is a bit restrictive.