I am quite frankly torn between the BK7m and PA3X. I really like both a lot, and there are advantages both ways. I particularly like some of the Roland styles, but then, I also like a lot of the Korg's as well. The Korg as so many great real-time operational features, that it shines in that category, and of course it has great vocal processing.
If the BK7m had a vocal processor it would be ideal.
It's great to have so many good choices, and I don't believe there is a wrong choice.
I did try the BK5 in the music store for maybe 30 minutes, and it didn't seem to sound as good (I was using headphones). Could well be e.q. and setup tweaks were needed though. I also didn't like the user interface. I am able to do so much more with an external controller and the BK7m.
I would not trade my E50 for a BK5. I have played it for the past four nights, while I do some tweaking at home on the Korg, and the audience couldn't care less.
DonM