I am interested in this topic also, as I am planning to upgrade my old Swing-based application to Java FX.
I haven't had experience with JavaFX yet, so my concern is whether JavaFX worth to upgrade? and how much effort would be made?
My Swing app is quite complex.
If you want to learn the changes in JavaFX and want to explore you can cutover to JavaFX codebase. I really cant comment on the effort required. But depending on the features used in your swing application it would varies. But definitely it will be a learning experience. I think its good to know JavaFX if you are working on Swing or Desktop based UI applications.