I play in a number of different bands, and my ideal would be to be able to circulate and share the repertoire of each band as a set of BIAB files. Even better is to share them in Dropbox, or similar, so that all band members get corrections and additions as soon as they're made, without anyone having to remember to send a copy of a changed version to a reserve player. This way, everyone has the same source file, and can use it for practice as well as for the production of a leadsheet for his instrument - hard-copy or PDFs for MusicReader or unRealbook etc.

Clearly, there are situations when BIAB is not the ideal music engraver (e.g. nested repeats), but I don't think it should fail to put chord symbols in the right place above the bars they refer to.

When I need a more sophisticated engraver I use Lilypond, which is at the geeky end of the spectrum, but gives me a lot of flexibility. It also has the advantage (especially to a Scot) of being FREE!

What would be really handy for me, when I come up against a brick wall in getting BIAB to present a song as I want it, would be an export_to_lilypond feature, which exports chord names as well as notes. I did find a program out there which reads the raw data in a BIAB file and exports the result, but this doesn't work reliably. If PG Music were to reveal the structure of the BIAB file I might even have a go at writing such a program myself, but I don't suppose they'd want to do that for perfectly good commercial reasons, and also because they'd then be constrained to stay within the published format.

What would also be handy is a BIAB grammar-checker, which can check files for corruption BEFORE they cause trouble. It's not uncommon for BIAB problems to be ascribed to a corrupt file, but without a definitive tool for the job it's hard to be sure if that's really the cause.