The comparison really depends on the type of user. Users who have
strong typing skills prefer the Trackpoint, users who must
look at the keyboard to type prefer the trackPad. Users who have never used a TrackPoint-type device prefer the trackpad as their limited experience with a trackPoint has not allowed them to tackle the learning curve of the device.
The TrackPoint has a much steeper learning curve than a TrackPad, it
takes several hours of continuous usage to learn accuracy with a trackPoint. That being said, after accuracy is acquired, the two are not comparable, the trackpoint wins hands down for any user who knows how to type and offers still offers some advantages for non typists, though these may find the learning curve less worthwhile. There are two distinct advantages to the trackpoint:
The TrackPoint allows the user to shift seemlessly from typing to pointer control without moving the hands. The speed improvement that this allows is stupendous, no need to re-register the fingers when going from pointer to keyboard, the hands are always ready to either type or point. That being said, this is not a great advantage to those who do not have strong typing skills. For those who can type without looking at the keyboard, there is no comparison between the trackpoint and trackpad: the trackpoint wins hands down. For those who must look at the keyboard to type, they may opt for the trackpoint as they will regardless have to look at the keyboard for finger registration.
Movements can be performed with one action, no need to reset the finger position when performing actions like moving across a larger portion of the screen. This can be offset in the trackpad by setting the pointer speed to max, allowing you to traverse the screen with a single stroke.
If you can type w/o looking at the keyboard, get a TrackPoint-type device, you’ll never ever go back to a touchpad device.
If you must look at the keyboard to type, stick with a TrackPad.