All details on Jasper's nice blog post [2].If you have 8 minutes to spare, I encourage you to have a look at this demo [3] where FX8 and SB2 shine.
-Simon[1] http://www.oracle.com/technetwork/java/javase/downloads/sb2download-2177776.html
[2] http://fxexperience.com/2014/05/announcing-scenebuilder-2-0/ [3] https://www.youtube.com/watch?v=ij0HwRAlCmo&feature=youtu.be