I've tried using FCKEditor 2.6.2 for an ASP.NET web application I was working on and it's really cool. You can check out a demo of the editor here:
http://www.fckeditor.net/demo
Unlike the version of FCKEditor on GWB (GeeksWithBlogs.com), we don't have a separate popup browser window. A common problem on GWB's FCKEditor is when you're done using the popup browser window, it doesn't automatically close.
The new version certainly ranks higher on user-friendliness.