What's the hardest part of moving from Swing --> SWT?

[Ramon F Herrera]

It seems to me that the path of least resistance is Swing, maybe
because it began earlier than SWT and it comes from "legitimate"
sources (i.e., Sun). Then, one reads that one of the fundamental
reasons for the success of Eclipse is SWT.

I have been writing Swing applications for a while now, but since I am
making the jump from traditional JBuilder to Eclipse, would like to
get my feet wet on SWT and, why not: JFaces.

Hence the question in the subject line. Are both toolkits really very
different?

TIA,

-Ramon