[agumonkey]

Depends, if you need OS interaction you'll need a posix-like subsystem indeed[1]. But first I write mostly lisp (ml, js and python) and I just can't live without paredit and second emacs extensibility is a drug to me now. Everytime I have to use anything else I feel crippled.

[1] I installed msys2 which is less crufty than cygwin.

[mappu]

Msys2 by design restricts the available packages to those useful for compiling software for Windows. The emacs package is in their separate mingw repository, which means the produced binary is a Windows program and does not understand the posix environment at all (i.e. no /proc/, /dev/ etc).

Cygwin is an OS that runs on top of windows - all cygwin programs are windows programs but not all windows programs are cygwin programs. The emacs package for cygwin can fopen() /proc/ and /dev/, use the linux socket API, and in general follow the linux makefile more closely.