I'm very grateful to Chris Walshaw. I've been using abc for 14 years to produce publishable camera ready tunebooks.
Admittedly I'm using the version balanced on TeX and MusicTex which was a kinda steep learning curve, but it makes the output almost infinitely flexible - something that expensive programs did (do?) not have.

And the music output is compact.

The transferability of it as text is invaluable. It was doubly so before broadband and high speed connections.

It also possible to compose using it - I have done so on several occasions, noting down themes on whatever flat surface comes to hand.
And with a bit of practice one can play from it (at need - I would not use it as a long term method).

Capn Birdseye's mileage obviously varies, but I've differed with him in silence in many threads so that doesn't surprise me.

My vote is for abc. I look forward to the programme.

Paws