The power of preference extension come in Item-Level targeting. This can be used to narrow the scope of which the extension applies to, for example users in a certain security group or time of day.
The targeting items that you can configure and use are these:
Battery Present
Computer Name
CPU Speed
Date Match
Disk Space
Domain
Environment Variable
File Match
IP Address Range
Language
LDAP Query
MAC Address Range
MSI Query
Network Connection
Operating System
Organizational Unit
PCMCIA Present
Portable Computer
Processing Mode
RAM
Registry Match
Security Group
Site
Terminal Session
Time Range
User
WMI Query
You can apply multiple targeting items to a preference item and select the logical operation (AND or OR) by which to combine each targeting item with the preceding one.