From my point of view, (none professional) I have BIAB but never use it when I have an arranger. As the arranger does everything that BIAB does but on the fly; ok it is an older version but a full version at that. I found you have to take your laptop with this version to play the files - unless they are midi, then I just use the keyboard anyway. Although, it has just died and I need a replacement..........

I also have a version of Sonar Producer 6 an older version true, it works well, but I don't use it unless I want to change an audio file.

Honestly if you could get an easy arranger software that works on the fly with your keyboard on a lightweight tablet, I would look into it. As I don't own a Mac or Ipad, but have laptops and Android tablets to play with.

Allan