You can get a little more detailed information like this:
PS > $PSVersionTable
Name Value
---- -----
CLRVersion 2.0.50727.4200
BuildVersion 6.0.6002.18139
PSVersion 2.0
WSManStackVersion 2.0
PSCompatibleVersions {1.0, 2.0}
SerializationVersion 1.1.0.1
PSRemotingProtocolVersion 2.1
And
PS > $Host
Name : ConsoleHost
Version : 2.0
InstanceId : [obscured]
UI : System.Management.Automation.Internal.Host.InternalHostUserI
nterface
CurrentCulture : en-US
CurrentUICulture : en-US
PrivateData : Microsoft.PowerShell.ConsoleHost+ConsoleColorProxy
IsRunspacePushed : False
Runspace : System.Management.Automation.Runspaces.LocalRunspace
I would interpret the "-1" values as "not applicable".