The recording of tracks seems pretty basic, but I have found that there are indeed some significant differences in the way the two receivers record tracks. Oddly while the Sportrak is almost legendary for it's supposed accuracy and reception capability, I've found it to be less accurate in general, and to suffer more problems in recording tracks than the eTrex.
To begin with, there is significant differences in the settings you can use to record tracks. In the auto settings, the Legend can be set up to record at least twice as many waypoints as the sportrak, and the Legend software seems to do a better job of recording changes in speed, direction etc. Distance wise the minimal distance the sportrak can be set to record trackpoints at is .01 KM, where the Legend can be set as detailed as once every yard. The Legend can also be set to record timed trackpoints at settings all the way down to once every second, while the sportrak has no timed function. The sportrak can record a maximum of 2000 trackpoints whereas the Legend has a capacity of 10,000 track points in the active log, and the ability to save tracks, albeit compressed in the number of data points.
As examples of how the receivers actually record tracks:
Comparison of tracks in good conditions: Here you can see how the track recording capabilities of the receivers compare in good reception conditions
Comparison of tracks in difficult reception conditions: Here you can compare the track recording capabilities of the receivers in tougher reception conditions.