title: Differences between MSYS2 and Cygwin
body: <p>Traditionally MSYS bash has been considered inferior to Cygwin bash. 
  The former was an ancillary tool inside MinGW intended for running autoconf scripts. 
  But now there is  MinGW-w64 and MSYS2. The latter ships with a sweet pacman like package manager and elegant shells like zsh, so I wonder if there is still a gap in the emulation layer. </p>
  
  <p>While MinGW* applications are Windows native executables, MSYS2 software requires a POSIX-emulation layer, just like Cygwin does. At least to a casual user, it is hard to spot the differences between the two. </p>
  
  <ul>
  <li>Which are the functional differences between the two emulation layers (if any)? </li>
  <li>Which emulation is faster (more efficient)?</li>
  </ul>