yWriter is available in several versions:
Of you might prefer to try Scrivener (not my software, but popular on the Mac)
yWriter5 BETA, yWriter6 and yWriter7 are all identical in operation. They're just compiled for different versions of Windows. (yWriter5 and yWriter6 don't work as well with unicode character sets.)
** Mobile versions of yWriter are designed for editing your PC projects on the go, using Google Drive or Dropbox.