Are you saying that /bin/sh isn't turing complete?

Not at all. What I'm saying is that /bin/sh has idiosyncratic, incomplete language syntax and semantics (mostly for historical reasons). For example, variable comparison is not built in but rather is dependent upon the external [ (or test). It would be hard to call a language 'complete' when it doesn't even support variable equality testing.

Whatever you think of Windows/MS/etc, Powershell is a decently-well-designed, complete language with a number of useful, convenient constructs. For example, here is a native Powershell hashmap (that can be looped over, etc.):

  $states = @{"Washington" = "Olympia"; "Oregon" = "Salem"; California = "Sacramento"}

Nice, no?

Powershell has lots of cool features, startup-time not being one of it. It's very important for some of these scripts to start in a matter of milliseconds.

Powershell starts pretty immediately for me. Older versions chugged, but testing on my desktop and laptop opened pretty much instantaneously.

Then I need to try it out again. After months of working only with Linux, OSX - I miss a bit the good ole NT :) - Far Manager, System Internal tools, WinDBG, etc.