I didn't have Midjpro, but I had Audya for a couple of years. The operating system on SD7 in much improved. Way easier to get around, save things, change things, etc. Big color touch screen is great. Audya of course has audio guitars in many of the factory styles, and it has WAY more factory styles on board.
I like the lead sounds better in SD7.
I still don't have enough practical experience with SD7 to have a complete opinion, but I'm learning fast, mostly on the job at this point!
I'm going in an hour early to adjust some things I learned researching the owners manual today!