This may be a stupid observation, but here goes. As an avid user of both BIAB and arranger keyboards (Yamaha at the moment), I wish it were possible to purchase and load BIAB styles in the keyboard and have them play like the built-in arranger styles, with appropriate fills and the like. Maybe it can, and I don't know how it's done. Maybe there are legal issues, or whatever, I don't know. All I know is that the BIAB styles are more numerous than arranger styles and better suited to my uses. I play BIAB midi files often through the keyboard and they sound great. I'd love to be able to play the keyboard in real time with BIAB styles that are professionally created specifically for arranger play-----and not styles that have gone through some kind of transformation process.