Cygwin is slow at things like process creation, I think, which made shell scripts slow. Plus, cygwin was its own environment that required some porting, or, at

Cygwin is slow at things like process creation, I think, which made shell scripts slow. Plus, cygwin was its own environment that required some porting, or, at least, recompiling to get apps to work. The new Linux subsystem runs Linux binaries at something like full speed (to the extent that I've played with it).