There is this trade-off between making it fast to do big mouse movements and making fine mouse movements possible. Typical high-friction PC touchpads are awful for fine movements. Trackpoints are good for fine movements, but they don't have enough travel to also make it easy to throw the cursor to the other side of the screen quickly. In my experience with both, the high-sensitivity, low-friction glass touchpad on the mac enables as much fine control as the trackpoint while also allowing sweeping large mouse movements.