I'm already using iRedMail and I'm greatly satisfied (and my customers too). They only complains about the long time it takes mails to arrive in their mailbox... but they can accept this since they are not receiving spam anymore.

What they are asking for is a full corporate mail-push solution. Mail-push doesn't mean only "real time mail delivery" (no one seriously misses it): most wanted features are contact and calendar sync.

I would like to build up a test environment to try iRedMail and Funambol. Did anyone already try it? Suggestions? Alternatives?

Thx