Oh dear God yes! Amplitude is
AMAZING!
So why don't more people know about this game? It has all the ingredients to be one of the better games in it's genre. Does it lack hype? Advertising? Gameplay?
Back in the day it definitely lacked both hype and any type of promotion. The only way I knew about the game when I picked it up in 2003 was because of a very good demo on one of the Official Playstation Magazine demo discs (or was it a Playstation UnderGround mailing?).
Let me just say right now that if you like Guitar Hero, you should definitely try this game out, because it plays exactly the same as Guitar Hero, but on a controller.
I also recommend tracking down Frequency, the "prequel" to Amplitude, as it is also quite good.