What are some alternatives?
When comparing Liquid Music and Synfire, you can also consider the following products
Odesi - ODESI is a music sketchpad that exports your projects to Audio and MIDI.
RapidComposer - MusicDevelopments RapidComposer: Music Prototyping and Automated Composition Software
Captain Chords - Write chord progressions in your favorite DAW
Helio Workstation - Cross-platform lightweight speed-painting tool for creating music.
Harmony Improvisator - Harmony Improvisator is the most advanced harmonic composition tool on the market.
Hookpad - Web-based music composition that greatly simplifies writing chord progressions and melodies