Well, there arn't any *known* issues other than the ones in the bugzilla.
I know of a cert error.
To be honest, more often than not, any install problems are caused by a previously unknown issue that resides on the server as opposed to the installer or ZCS itself.
A perfect example is a bug we discovered with not having free space on the / or /tmp dirs. It caused the script to fail, but the admin should have checked the avail space before running the install.
There are currently 32 known issues related to OSX. You can view them here:
http://bugzilla.zimbra.com/buglist.c...op&value0-0-0=
The only *critial* bug is 7039