I you type "Start-VM -name <TAB>", it won't list the list of the VMs, but rather the list of the files in the current directory. That's not exactly what I would call insightful.
I didn't know about the CTR+SPACE. That being said it doesn't seem much more insightful than TAB. And no description of what the argument does.
The issue with "Start-VM -name <TAB>" is not an issue with Powershell itself, but with the Start-VM cmdlet; the Start-VM cmdlet could have been designed to complete from the list of VMs.
I didn't know about the CTR+SPACE. That being said it doesn't seem much more insightful than TAB. And no description of what the argument does.