On Windows, the installation has now become easy with a installer, under debian, no major problems. Lilypond is a bit like LaTeX: you have to delve a bit into it to get to do something, there is a time of learning unlike other software, but nothing insurmountable.

SUITABILITY/PERFORMANCE

The performances are excellent (of course the software is a bit slower on windows)
the rendering quality is amazing, it looks like a professional score! more, you get a pdf file which is very convenient (even if we can export to other formats for web-pages)
the software is very stable (no bugs apparent) and finally easier and faster to use as a software graphical user interface (once you get used to) ...

OVERALL OPINION

I use this software for 2 months, the most impressive is the final rendering. This software has four advantages: it is completely free (so in particular free) and so it is evolving very fast (bug fixes etc ...) and it works under different OS.