What are some alternatives?
When comparing Impro-Visor and Band-in-a-Box, you can also consider the following products
MuseScore - 24 Sep 2012 . Design a homepage that captures attention and serves as a good starting point for navigating the website.
Odesi - ODESI is a music sketchpad that exports your projects to Audio and MIDI.
Guitar Pro 7 - Create, play and share your tabs
RapidComposer - MusicDevelopments RapidComposer: Music Prototyping and Automated Composition Software
Sibelius - Sibelius is a virtual score creation tool which allows composers to easily create new piano scores, developed by Avid.
TuxGuitar - A Multitrack tablature editor and player.