Rocksmith is a game developed by Ubisoft. It's key feature is the fact you can plug in any guitar into your console and play a song; which takes guitar Pro mode in RB3 and makes it better. My only thing with this game is it will still have a hard time pulling a demographic from either GH or RB. But considering the cost savings and the fact you get to use your own guitar might be worth it.
Rocksmith is a game for guitar enthusiasts. Whether you’re a beginner who is starting to pick up the instrument or a seasoned shredder, Rocksmith aims to make use of the guitarist in you.
Platforms: PC, 360, PS3
Expected release date: Fall 2011
http://www.ubergizmo.com/2011/03/ubisoft-rocksmith/
http://rocksmith.ubi.com/rocksmith/en-US/
edit: edit for possible misinterpretation