BIAB was almost entirely responsible for my waking up a 40-year keyboard "talent" and starting to actually play again. The program, once learned to some extent, will "push" you as fast as you can move to improve your skills. I moved from arrangers (great tools, had 6) to BIAB and have migrated to solely BIAB and piano VST, mainly due to better sounds, more sounds, the flexibility one has with styles, voices, timing. And perhaps most of all I enjoy participating with a growing batch of BIAB users who appreciate the fantastic job the PGMusic gang has done to bring the program to the stage it displays today.
For me, happily playing (better) again at age 76, it has been a life-changing piece of music software.