search for: locohost

Well, I stumbled onto zimbra.... I have a Scallix system built, but still have some rough edges to try to smooth. Like the way it works with sendmail, no dnsbl's will work as sendmail sees all mail as coming from locohost (scalix). Still battling that one which is when I ran across Zimbra. So, this made me start wondering. Are there other exchange server-like products out there? Has anyone dealt with Scalix and Zimbra (or another from the question above) and would you care to post pros and cons to each? Some o...