I had a Trackpoint for four years on two laptops. I had to give it up because I wanted a very specific configuration for my new laptop and at the time having a Trackpoint on the new laptop would have added $4000 to the price of a $2000 laptop (or perhaps more accurately, I saved the difference by choosing a configuration that happened to use a Touchpad instead of a Trackpoint).
The key to understanding trackpoint is that it is pressure sensitive. Once you figure out that your finger is supposed to touch the thing and stay stationary (the opposite of the touchpad behavior), then it just becomes a matter of learning to dole out pressure relative to where the mouse should go. Combine this with an exponential acceleration curve and Missile Command is easy with the trackpoint. Using a bunch of ordinary desktop applications is trivial. There's a large range of usable input pressure levels but no motion of the finger in space, so it's about as close to directly connecting a mouse pointer to my brain as it is possible to achieve without electrodes. It's better than a mouse for anything except for Quake (although I did finish Quake III Arena in the second-easiest mode with the Trackpoint, just to prove the concept).
One thing that I found quite helpful is to replace the standard pencil-eraser-shaped rubber tip on the trackpoint with a concave version that the finger fits into. There are also flat-topped variants but the concave "cup" shape gives the largest degree of control.
I am able to use the Touchpad, but only after replacing its default configuration. I have to turn off touch-clicking, since it would otherwise randomly drag or click on things while I'm trying to move the mouse (or often when I'm not trying to move the mouse). Drag is a two-finger operation (actually finger on touchpad and thumb on button) for me. I turned on the horizonal and vertical scroll areas on the bottom and right sides--somewhat unreliable but mostly harmless, it's more useful to have scroll than it is annoying to have scroll randomly become mouse movement and vice versa. Other settings are less important, like changing the button mappings and fingertip size.
The Touchpad cannot win the contest because it needs huge finger motions due to its low input resolution. It is tracking the physical motion of an object the size of my fingertip, so increasing its sensitivity just adds noise to the cursor position.
It occurs to me that there is probably enough raw data present in the Touchpad device (internally it produces a 2D map of physical pressure values) that it could be programmed to behave almost the same way a Trackpoint does. That would be sweet...