@bhwong
1) it takes around 13 min for me to install CentOS 5.3 + yum updates + pre reqs + Zimbra using PXE and KS

2) if we do from CD 30 min flat including installing zimbra
3) "
have to put yourself in the shoe of the end users, especially those who never touch command line and linux before"...well if a user who wants to really manage and run zimbra never touch commmand line then they wont be able to "really" manage and run zimbra (or any email server) in real life..so giving them a VM with "everything done for them" will be of no use as they cannot manage that one either.
and on top if user dont know how to use linux then how they will manage the Vmware Server ? and do all the configs needed
if they just want to see what zimbra is online demo is there.
4) zimbra install "is" idiot proof..if user is "Reading" before installing.
5) Mac is not user freindly..i like windows

..ask the guy herehttp://www.zimbra.com/forums/installation/32662-nightmare.html
6) windows is user freindly..by Exchange is even bigger pain to install than zimbra..so i like zimbra
..just my point of views..igmore the mod badge.
Raj