The displays & Os look very similar just wondering & does the SD7 add more features....?

There are only minor differences... But they are there,

I'd like to know the A/B differences between the SD7 & Midjay pro?

There is one major difference. SD7 has keys.

MJPro = 143 Built in styles (you can load more styles as you wish)
SD7 = 260 Built in styles, more voices & more real-time controls.

Other than that, they're very similar, OS and sound wise. Just a caution thouh, after owning and using Ketron Audya, MJPro or SD7, you may get dissatisfaction blues with your other arrangers. The liveliness of the styles are so excellent that you're gonna miss them when you play your other arrangers. I was very impressed with my Korg and Roland styles before due it's 'realistic drums', now they sounds lame/robotic to me.

I hear you Jimmy....