What are some alternatives?
When comparing SingStar Dance and PaRappa the Rapper 2, you can also consider the following products
DJ Hero - DJ Hero is Music, Rhythm-based, Single and Multiplayer video game developed by FreeStyleGames and published by Activision.
Rock Band - Rock Band is a Rhythm Music and Single and Multiplayer video game created by Harmonix and published by MTV Games.
Performous - Performous is a Music and Dancing Simulation released by Loud Arts.
World in Audition - World in Audition is an Addictive, Dancing and Music Simulation.
Michael Jackson: The Experience - Michael Jackson: The Experience is a Rhythm, Music, Single and Multiplayer video game created and published by Ubisoft.
StepMania - Rhythm game for Windows, Mac, and Linux.