What are some alternatives?
When comparing Impro-Visor and MuseScore, you can also consider the following products
Guitar Pro 7 - Create, play and share your tabs
Sibelius - Sibelius is a virtual score creation tool which allows composers to easily create new piano scores, developed by Avid.
Band-in-a-Box - Band-in-a-Box is so easy to use!
Finale - Finale, the world standard for music notation software, lets you compose, arrange, notate, and print engraver-quality sheet music.
TuxGuitar - A Multitrack tablature editor and player.
LilyPond - GNU LilyPond is a computer program for music engraving.