How wonderful it was to experiment with these new fonts.
In particular, I enjoyed the documentation. It was exceptionally clear how to use them (including the 2.18 patch, though I ended up upgrading to 2.19 anyway.) The .ily files that demonstrated the fine tuning were really helpful and pointed the way to really customizing things. This is the first time I have felt that I can really start to control the visual aspect of Lilypond output. I have not yet attempted to do the mixing/matching between fonts, but expect to do so at some point, as I found that I preferred different aspects of different fonts.
The single font I like best is Cadence. While it doesn't seem to have any truly characteristic glyphs or implicit swagger, it has the best balance of glyph sizing. In particular, the natural/flat/sharp symbol size, as compared to the note heads (large but not too large), as well as their relative size to each other (some fonts seemed to have sharps that were much bigger than flats, etc.) seemed to be what I noticed and cared about most when comparing the fonts in actual use. Beyond that, I tended to like larger, curvier flags (Paganini, Haydn, Sorlatti) and medium sized articulations (Beethoven, Cadence, Paganini), so once I narrowed the fonts down based on the accidentals, these other considerations led me to choose Cadence as my go-to font. I've also found Scorlatti to be very elegant where there aren't so many accidentals.
I know that your work on the LilyJAZZ font was more about completing it, than designing it, so this comment really isn't directed towards you. On the one hand, I really like the concept of a handwriting-style font. But LilyJAZZ seems more like a display font, than one you would actually want to use to typeset a whole piece.
Thanks again for your amazing work. I hope enough folks kick down some paypal love to make this worth your while!