Good idea, but....
....Elite Beat Agents style games are difficult to play on a computer.
I played using a tablet, and I found that it was a good game to get your tablet control skills up. That being said, it was difficult to get every note perfect, and as XceeD said, there was indeed a large gap between a miss and a perfect.
When I used a mouse, I could move to the notes quicker, but I had less control on where I was going. Since most notes went only in horizontal and vertical patterns, this wasn't too much of a problem.
The visuals were very appropriate, and the song choices were superb.
But if you want to play something like this, get Elite Beat Agents and a DS (or a very small graphics tablet).