Hi Charlie,
I own a Roland VA7 and the morphing feature allows you to "paiste" in real time parts from different styles (you can choose from "drums", "bass" and "accomp." This feature takes one or two of these parts from a style AS A WHOLE and mixes them istantly with the other 1-2 parts from a different style. For more subtle (and MUCH more time consuming) editing you have to access the style editing area.
Given the number of excellent Roland styles available on the net, I would say that there is almost no need to program one's styles.
Regards from the other side of the world.
Andrea