A new PowerShell 4.0 bug has been submitted through Microsoft Connect, and is good to know about if you plan on utilizing the functions the bug affects.
The report bug covers the Get-ADComputer -Properties function and results in an error message about Invalid Argument.
The bug has been submitted to Microsoft Connect and already has a few votes. If you are affected by this, or believe you will be affected by it at some point, you should drop out to the Connect site and vote-up the entry so that it gets priority to be fixed in a coming update.
The report is here: Windows 8.1 - Powershell 4.0 Get-ADComputer -Properties * bug
Others have reported that this bug also exists in get-aduser and get-adprincipalgroupmembership.