I jumped in bed with MIDJPRO after a 8 years long relationship with the first model of the MIDJAY. Not the PLUS.
It appealed to me greatly because it sounded so much better compared to everything I've played using the older MJ.

BUT:

There's a lot of balast they putted into it - that leading to a high price... Fancy DJ things which probably 5% of the users may benefit from.

It's been a 3 months challange to set up the MIDJ PRO with all the styles I've been previously using. The internal styles are more than great, but soo few.... At the price we'd paid for it, I would expected it to be well equipped with a much larger style library... But no.
And so I went back converting styles, rearranging drum notes, and changing instruments, attempting to give a new life to the old Ketron styles.
After 13 months, it is still an ongoing process. I am almost there.

My conclusion?

Regarding your matter, if you are satisfied with your MJ Plus, DO NOT ENGAGE with the PRO. It will eat your heart out, your nerves, and your time to an extent that you'll start regretting the decision of buying it.
I personally know such cases.
So, unless you are commited to painful and hard work, please, enjoy your MJ Plus.
Ketron MIDJPRO is nothing like Audya compared in styles library, ease of programming and adjusting styles. I have them both, so I speak from my personal experience.

My personal understanding of the way Ketron is doing business with us, is that they lack the practical knowledges regarding the mainly use of MIDJPRO.
Or they suck at marketing.
Or they do not respect their clients, like Yamaha or Korg do. Roland is out of question for some time...

Take a deep breath, be honest to yourself, and decide consequently. Now you know the truth.
Or maybe it's just me...

This is an open debate, and I'll be more than satisfied to read Ketron's point of view, right here!

P.S.
Ketron will NOT take any action to improve their customer's support or upgrading their products up to their customer's expectations. They just can't. I guess it's a big hat to wear nowadays...