Extract version string from text file with Powershell
I haven't found a terser approach using only built-ins, but having a little more confidence now in Powershell, I think I'd simply refactor out the group matching code:

filter Select-MatchingGroupValue($groupNum) {
    if (! $groupNum) {
        $groupNum = 0
    }
    select -InputObject $_ -ExpandProperty Matches |
        select -ExpandProperty Groups |
        select -Index $groupNum |
        select -ExpandProperty Value
}


Then you could use it like:

Get-Content .\somescript.vim -ErrorAction SilentlyContinue |
    Select-String '^" Version: (.*)' |
    select -First 1 |
    Select-MatchingGroupValue 1


In the end, you haven't saved that many lines, but refactoring out the tedious expansions of Matches, Groups, and Value makes the resulting code much clearer IMO.