Group Policy Tips:
1) The Microsoft Group Policy Management Console (GPMC) is the best method to manage group policy without purchasing additional tools.
Some 3rd party vendors had tools like this for Windows 2000, but finally Microsoft simplified management of group policy through native tools.
to read more and download look at:
Where can I download the GPMC console for Windows Server 2003/XP?
2) Specifying a Domain Controller for Editing Group Policy
This goes into detail the way the tool at times uses the DC which holds the PDC emulator role, espically when performing an edit on a GPO.
3) When creating a policy be sure to select templates and remove all unneeded templates.
Group Policy can process fast and you can have some levels, the real thing that takes time to process is the ADM files. Removing unneeded template will cut down the ADM files.