What are some alternatives?
When comparing Guitar Hero and Rocksmith, you can also consider the following products
Clone Hero - Clone Hero is a free rhythm game, which can be played with any 5 or 6 button guitar controller...
Frets on Fire - Bonus content.
StepMania - Rhythm game for Windows, Mac, and Linux.
Audiosurf - Audiosurf is a music-adapting puzzle racer where you use your own music to create your own experience.
Osu - Osu is Music, Rhythm, Single and Multiplayer video game developed by Dean Herbert.
Incredibox - Express your musicality, pump it up and chill