I am just cincerned with the small buisness version. If one assumes that the customer
changes their email system every 3 years (in practice may of my customers leave it five years) This means Zimbra is end user price £2500.
I did a speadsheet (I do not have it here) and I put in 5 10 15 20 etc up and then put prices for OEM small buisness edition (this includes Windows 2003 and SQL).
I know that Zimbra was more expensive for all the smaller number of users however I seem to remember that it was more for 50 users. I will email the spreadsheet.
It is difficult to do trade costs as I have not got these for Zimbra. At the other end we would need to compare costs with Microsofts OSL (open subscritption Licence or whatever it is now called) I have not checked that.
What is worse is that many of my clients in the health and education sector get very high discounts.
With respect to functionality it is shared calendars, then contacts and integration with PDF that is all they want.