LinuxMusicians

You forgot MUP www.arkkra.com, which is also very powerful, mature and continuously developed. Distributed in sourcecode but not free software or open source (you need to buy a license).

Hi there!

I'm new here, professional organist and using Linux since April 13th, 1999, exactly

I'm also an avid LilyPond user, and wrote a nice little LilyPond plugin for KDE's Kate, called LilyKDE.

And PS, yes: from the Netherlands