In his post "Non-Native UI Sucks" Jeff states:
When two applications with rough feature parity compete, the application with
the native UI will win. Every time. If you truly want to win the hearts and
minds of your users, you go to the metal and take full advantage of the native
I'm not even sure the native application has to be at parity with a competitor to win.
I also agree with Jeff's comments about the Java UI. UGGG-LYYYYYY. And SLOW. Never met a Java app I didn't hate.