I know some people love them but compared to the massive glass trackpad with multitouch that I have on my MacBook I don't understand the appeal. Is it a portability thing?
Mind you, I'm only speaking for the real ThinkPad trackpoints. The one in a Dell laptop I had for work was nowhere near as comfortable, and felt slippery and awkward.
I fell in love with it after building a large bulk of an app on the 17 express bus over the course of a year.
Trackpoints are better when in a cramped situation such as air travel. No readjusting of elbows are required when switching between keyboard and trackpoint.