Nisus Writer Express Version 3.4 brings some new features, many fixes, and compatibility with forthcoming Mac OSX Lion (10.7). Among the new features are a vertical ruler and special characters menu/palette.
If you'd like to try this pre-release beta, download it here:
http://nisus.com/files/express/NWX-v34-p1.zip
Please note that this beta is not the final release of Express 3.4.