I've been testing the appliance for a while and noticed that it behaves differently when deployed via vCenter as opposed to directly connected to an ESXi host with the vSphere Client.

vSphere Client to ESXi host:

The different options outlined in the Setup Guide are not present. Quoting from the guide none of these are shown:

"6. Select the deployment configuration for the appliance.
• Trial. Select Trial setup if Zimbra Appliance is being deployed in a non- production lab environment.
• Midsize. Select Midsize setup if Zimbra Appliance is being deployed in an environment with less than 500 users.
• Large. Select Large setup if Zimbra Appliance is being deployed in an enviornment with up to 1000 users.
Click Next.
8. Select the IP address allocation scheme appropriate to your network configuration. For most Zimbra Appliance environments select Fixed. The IP addresses are manually configured on the Properties page that follows. No automatic allocation is performed.
Note: To automatically configure the appliance trial server’s network configuration, select a destination network with DHCP services configured and running.
9. With the properties page open, configure the following details for Zimbra Appliance.
• Configuration Password. Enter the password for the Virtual Appliance Management Infrastructure (VAMI). When you log into the Zimbra Appliance console, you enter this password.
• Server Name. Enter the Zimbra Appliance hostname. This is the server name. For example, mail.company.com.
• Administrative Account. Enter the name of the administrator’s account This account is automatically created on Zimbra Appliance during the install.
• Admin Password. This is the password to log on to the Zimbra administration console and to log on to the administrator’s mailbox. The password must be at least 6 characters.
• If you selected Fixed as the IP allocation policy, enter the network IP address
Click Next."

vSphere Client to vCenter:

The OVF deployment wizard asks for the configuration information above.

Also, the appliance seems to discard the fixed ip configuration during deployment and always reverts to DHCP.

I'm hoping that the next version of the appliance 7.0 is more robust because there are quite a few quirks/bugs with the current one.