OK , since a good deal of this thread is about is there anything else out there besides BIAB …
it is my duty to mention one of the best open source freeware options out there …
Impro-Visor
https://www.cs.hmc.edu/~keller/jazz/improvisor/ Impro-Visor when it first came out was geared more towards Jazz players who want to explore the advanced elements of improvisation . As it has grown in acceptance and gotten a larger user base it has added other genres
( I still use it mostly for Jazz and I haven't added the other styles yet )
Impro-Visor is not as sophisticated and complex as BIAB when it comes to creating backing tracks of various musical genres , Yet Impro- Visor does in fact hold its own up against anything I have ever heard when it comes to creating improvised solo's over chord changes …
I have used this program for about 3 or 4 years on and off and I can say the vocabularies it bases its solos on are shocking …one of my favorites is the Bill Evans vocabulary ….
Anyway , Impro-Visor is a little quirky and takes a little getting used to ….The onboard synth sounds cheesy , but once an export of your song / improvisation is done as a midi file , you have the option to go full tilt in whatever DAW you happen to want to use for your VST sounds….
The main gist of this app is to create solos to play and analyze, so the backing parts are a little light ….
Also Bob Keller's personal site is a goldmine of excellent resources if you happen to be into Jazz oriented learning resources …
in other news ,
bapu , I really enjoyed your post and you are making a lot of sense on how you use BIAB …
Kenny