One thing to consider: Screenreaders
For some reasons, some Swing components do not work well when using a screenreader (and the Java AccessBridge for Windows). Know that different screenreaders result in different behaviour. And in my experience the SWT-Tree performs a lot better than the Swing-Tree in combination with a screenreader. Thus our application ended up in using both SWT and Swing components.
For distributing and loading the proper SWT-library, you might find this link usefull: http://www.chrisnewland.com/select-correct-swt-jar-for-your-os-and-jvm-at-runtime-191