Typically, my registrations are fine tuned for specific songs. So, creating separate user styles, voicetron settings added more steps and assigning names to them. I found it easier and straight forward to tweak styles, voicetron etc under registration. But, it's good that Ketron has multiple ways to these.

PS
I was surprised when I upgraded to SD90 from MidJay Pro. I just copied all the MJPro registrations to the new SD90 and and it works almost 100%! I didn't copied any styles or user styles from MJPro.