For those bound to Windows, GNU Emacs 23.4.1 (i386-mingw-nt6.0.6002) provides a current version with an installer as part of the DL---actually the installer is the initial DL, the rest is done as part of the install. In so far as I can tell comparing Unix version(s) with the Windows version there doesn't appear to be any difference in ability or performance. The http://www.gnu.org/software/emacs/windows/big.html does a reasonable job of covering the water front for better information than mine.