Searching for a Directory Service Solution?

kumulan wonders: "I've got the responsibility to set up directory services as well as a messaging/groupware system for my organization of app. 100 employees spread out over three locations. We are a startup that is merging three existing smaller companies and, given the state of existing IS infrastructure at each of these locations, the decision has already been made that we are better off starting from scratch. It would be great to hear from Slashdot readers concerning which option is 'better' and why." "For me, the choices are stark and clear:

1. MS Exchange/Active Directory
2. A cobbled-together solution based as much as possible on OSS (as no direct equivalent exists).

For (2) we have evaluated, and are strongly considering, the following:

• Samba/OpenLDAP/Kerberos
• Bynari Insight Server for messaging/groupware.
• Nitrobit Group Policy for, you guessed it, group policy management.

Of course, Samba 4 will address some of this 'cobbling', but we can't wait for that."