Long replication times are experienced everytime a replication is performed in the Desktop Authority console.
By default the option "Update only changed files" should be checked in the replication options for Desktop Authority. If the option is unchecked all the files from the slscripts share on the Desktop Authority server will be copied to the Netlogon share during replication.
In the Desktop Authority console navigate to Deployment Settings | Server Manager | Replication Options. Select the "Edit" button and check the "Update only changed files" option. Once the change has been made select Save and Replicate. The replication should be faster because only the modified files are being copied during the replication.