Friend of mine from YourAdmin.Ca posted an interesting opinion about Symantec Endpoint Protection 11:
After two month of intensive using of the newest product from Symantec – Endpoint Protection (SEP) 11 – I am ready to make a statement: you want to wait at least till the first service pack before deploying SEP in production.
If you decide to try anyway, spend time to develop proper policies before clients installation. Turn off all features that you do not need at the moment. Pay close attention to Network Threat Protection and Outlook Auto-Protect features. May be it will be better to refrain from using them so far.