jEdit was basically my first introduction to powerful text editors while learning programming and Lilypond. It had some nice plugins/macros for text processing. But, yeah, it was so slow that eventually I moved to Notepad++ for basic text viewing/editing. Recently I decided to give ST2 a try and am very pleased with its speed and features. Right now I'm trying unlearn a few Notepad++ shortcuts that I occasionally misapply to ST2.
Having jEdit load on startup helps a bit with the slowness.