The default properties that are displayed after a Get-Datastore is not everything that is there.
To see all the available properties, do a
Get-Datastore -Name MyDS | Select *
If you still need more info, have a look at the vSphere Datastore object.
The good news, you have access to all that information through the ExtensionData property.
For example, to get the maximum filesize of a file that can reside on a specific datastore.
That info is not directly available in the Datastore object that is returned by the Get-Datastore cmdlet.
Watch out this last Datastore object is not the same as the vSphere Datastore object !
Back to the example, to get that information you could do
Get-Datastore -Name MyDS | Select Name,@{N="Max Filesize";E={$_.ExtensionData.Info.maxFileSize}}
Hope this helps you a little bit on your path in the wonderful world of PowerCLI 