Right now, I'm either using SWT or Qt (Jambi).
Swing didn't evolve in the last, say, 10 years, bugs aren't fixed, the development has stopped in favor of JavaFX, so you won't ever see any new features, too. JavaFX will probably look great but is still vaporware and it's made by the people who let Swing starve to death, so I'm not putting any money on it.
Between SWT and Qt, I prefer to use Qt because it's a very mature and powerful framework made by people who know what they are doing (well, most of the time anyway :)) and SWT if the license for the new project wasn't compatible to Qt's.
