A compromise between a useful shell and learning something which only has value on windows, a platform of declining relevance to the world of servers, is bash. Git for windows comes with bash and it's nice to have one common shell as I move across os x, linux and windows. powershell looks very interesting but I have not been able to justify learning it yet. For more advanced admin python on windows works well and once again there is not a new learning curve. I wonder if the new Microsoft would have done something as idiosyncratic as powershell.