The 'for-each' looping definitely makes transition and deployment processes easier. My team and I have designed a few Powershell one-liners to move mailboxes and set UM settings. Below is two examples:
Move-Mailboxes using a CSV File: (This can run in multiple Powershell sessions)
Import-CSV Users.csv | For-Each {Move-Mailbox -Identity $_.UserAlias -TargetDatabase $_.Database -BadItemLimit:10 -Confirm:$False}
UM Enable Mailboxes with Extension Numbers:
Import-CSV Users.csv | foreach {Enable-UMMailbox -Identity $_.UserAlias -UMMailboxPolicy 'San Leandro UM Dial Plan Default Policy' -Extensions $_.ExtNo -Pin '1234' -PinExpired $false}
One-liners are going to save a mass amount of time for Administrators, Consultants, and etc..