You are comparing two things at very different prices, though. BK-7m can be got for under $1000 new, as far as I can tell, Midjay Plus is about $1700, right (new)?

I like my BK-7m, but think there's a few things the OS needs (that have been added to the BK-9 OS). First is the Mark/Jump for SMF's (if you aren't using this, you aren't getting the most out of your SMF's), second is the Dynamic Arranger (backing gets louder or quieter depending on your playing dynamics), and lastly, it needs the BK Performance editor iPad app to work with it.

Hopefully, Roland can update the OS for these things rather than a new model...

For more forward looking arranger players, a decent WS (Motif, Krone, etc.) married to a BK-7m is quite a potent combination.