One of the things that I think they've done right, is that they're doing integration well. They integrate with IMAP, LDAP, and Samba. It comes with an installer that installs all of those for you, or you can use the servers you already have running, supposedly. I don't know the details.
Unfortunately, it's not open source. They charge $1,250 for the first 10 user license. So I can't check it out.
But I do want OpenACS to look something like that out of the box. I want an installer that has several standard configurations built in (groupware, company web site, intranet, dotLRN, clean, ...), and I want this to be one of the configurations available.
But please do take a look at the demo, and let's figure out how we relate to something like this.