An excellent notation editor that is across platforms to create any kind of score from lead sheets to orchestral scores.
Pros & Cons:
MuseScore is an excellent notation editor that is compatible with Windows, Mac OSX, Linux, and FreeBSD. It is capable of creating the notes, symbols, and lines that you'll need for almost any kind of score, from lead sheets to orchestral scores.
MuseScore's interface is very well laid out, and it even provides a "Getting Started" sheet music file that walks you through basic note editing. You'll notice that nearly every visible element on your sheet music can be right-clicked for more options, including a "help" option, which searches the online handbook for relevant pages. While I was able to find some elements that didn't yield help articles this way (try searching for help on "staff text"), this is still an extremely convenient feature, and you can also find answers on the MuseScore forums.
MuseScore has a strong set of features. It can play back your music, using either its own soundfont file or another that you specify. It can open MIDI, musicXML, and a few proprietary save formats. It can also export to a variety of files, including MIDI, musicXML, audio, PDF, and PNG. In addition, the MuseScore site hosts a small library of plugins, which automate certain tasks. I only have a small complaint about the note selection function, which is a little difficult to use. Overall, MuseScore is a great choice for any kind of job.
MuseScore was reviewed by Gizmos Freeware on based on version 2.0.1.