I wasn't referring to jerkiness, but the fact that over time the position of the mouse drifts (the same point in the air doesn't correspond to the same position on the screen, so in the worst case you'd walk around the room).
Something about integrating acceleration twice to get position introducing errors.
But I looked at that same product and thought it'd be interesting, but elected not to buy it. I'll trust you if you say it was a good product.
The motion controller in the HTC Vive, if I read it correctly, have IR LEDs or some kind of laser tracking with an external station to keep absolute spatial position. The headset I know does this for sure. Carmack mentioned that Oculus tried the accelerometer-gyroscope only solution and it didn't work out.
Mousing isn't quite as concerned with precision as VR, but the same issues remain.
So... integrating a Twiddler with an HTC Vive or something... that would be fun.