So I buy a M$ small business server essential package to replace an existing 2003 small business server. The rep and info stated it had exchange built in, but no, exchange is an add on for almost $1000. I almost flipped. I immediately started looking for an exchange replacement and came across Zimbra.
I had to install it 3 times before I got it right but it was due to running it on an existing bind/apache server.
Once up and running I simply LOVE it.
And using the open source version the price is unbeatable.