Take a zip file (for the sake of common ground take the zip file Pscx-2.0-Beta2.zip) and run:
Expand-Archive -format Zip -Path d:\downloads\*.zip -OutputPath .\Temp\ -ShowProgress
The contents of the files are date/time stamped with the time of extract. Folders are suppossed to be (as I understand it), but the files date/time stamp is not preserved.
Also... it seems that the cmdlet will show progress whether or not the flag is present.
By the way - love the xcopy deployment. MUCH better. Thank you!