One problem (showstopper) we have with Scalix is that it seems to want to take over the Outlook profile - you need to create a Scalix profile, which I take to mean a "Scalix message store". I bring this up here, because Zimbra's white paper (http://www.zimbra.com/pdf/Zimbra%20M...on%20Suite.pdf)
says that you can still rely on the default Outlook message store - which I take to mean the default Outlook Profile, when you go to Control Panel > Mail > Profiles.
If all I said is correct, then I think this is a huge selling point for Zimbra because it makes it easier to integrate.
... but is my understanding correct?