If you want a cross-platform groupware server with even more features, you can add Kerio Connect to Mountain Lion Server. Kerio Connect (
www.kerio.com) is considered by some to be an alternative to Microsoft Exchange for small to mid-size businesses, and it syncs with Active Directory and Open Directory. The big advantage over the built-in groupware of Mountain Lion Server is that Kerio Connect supplies e-mail, calendar, contacts, notes, and tasks to just about any client: Outlook for Windows and Mac, Entourage, Apple Mail, Calendar and iCal, and Contacts and Address Book.
Like Mountain Lion Server, Kerio supports iPhone, but it also supports BlackBerry, Android, Windows Mobile, Symbian, and Palm Treo. The remote console is cross-platform, too: You can manage Kerio Connect from Windows, Linux, and Mac OS X. The server is also available for Windows and Linux.
Kerio MailServer has some expanded features, too. Although Mountain Lion Server lets users delegate calendars to other Calendar and iCal users, Kerio Connect lets users delegate calendars to Outlook and Entourage, as well as to Calendar and iCal users. Another thing that Kerio has that OS X Server doesn’t is integrated, automatic server backup.