Hey Jerry T!
I own Midjay since nov.I had SD1+ before so I'm pretty ok with Ketron way of thinking.
I'm using Midjay everynight and I found it easy to work as long as you get acomodate with the system..like any other arranger in fact.
So, while you play a mid you can select a Mp3, style,registration,wave and so on.Single problem is when you have a text runnig with mid, you have to exit text screen to search for anything else.
About registrations..is very simple, like user program in Roland.You can "record" all the settings like style (twist),patch for right hand,also for left,EQ,effects ...in a file with a certain name ,let's say "Twist Again", then Midjay has a button "Registrations" calling a folder in the root of the HDD...all you have to do is to scroll and select the one you want.I didn't used any playlist yet but I'll experment this days.
Hopes this helps a little.