I am a long time Emacs user. Yet although I’m comfortable with the editor, I have never really achieved “power user” status with it. I dabbled with some macros and I fiddled around with my .emacs file, but I never got around to creating any non-trivial code to extend the editor in a useful way. Also as much as I respect Emacs, I’ve grown somewhat tired of its old fashion and rather quirky interface. Thus I started looking around for a more modern editor that, like Emacs, would be powerful, extensible, and free.
I found jEdit.
I like the fact that jEdit is cross platform. I use both Windows and Linux systems extensively and, like Emacs, I can run jEdit quite nicely in both of those environments. I also like the fact that jEdit can be extended with Java plug-ins and Beanshell macros. jEdit has plenty of features, particularly with the help of a rich collection of third party plug-ins, and it sports a much more modern interface than, well… Emacs.
My only complaints about jEdit are: 1) The interface is ugly, and 2) The quality of the third party plug-ins is quite variable. Some of the available plug-ins are very nice and work wonderfully. Some are rather rinky dink. Thus one’s experience of using jEdit depends heavily on which plug-ins are involved.
Overall, however, I find myself liking jEdit more all the time. Lately I keep jEdit running constantly on my desktop and use it for all my text editing needs. In the past I ran Emacs that way, but lately Emacs has been relegated to occasional, specialized use. Now I feel like I’m ready to take jEdit to the next level and begin creating some macros and plug-ins for the complex editing tasks that I had always planned to do with Emacs some day.
Is jEdit a worthy replacement for Emacs? Maybe so.
Technically Rambling 
I’m also a long time Emacs user (~15 years). About a year ago I started looking for a more modern editor and came across jEdit. It is a fantastic editor!! It has almost all the power-features I loved in Emacs, but with a better UI, plug-in framework and macro system (you can even write macros in Groovy or Python!). It has totally replaced Emacs for me.
I have to agree that the UI is not beautiful but there is work in progress to update the icon set to give it a more fresh look (see http://mijav.dk/?q=node/18). The new icons set will be the default in the next (pre-)release.