I've used Sportstracker for about a year now on my Nokia 6220 Classic (Model 6220c-1 software version 03.46 26 Sep 2008) and have been very pleased. Recently I upgraded to the latest version of SportsTracker (2.06) and I find that the accuracy of distances has suffered.
I noticed see this because when I repeat workouts that I did pre-2.06, the distance is now much longer.
Not being sure whether the new version was more or less accurate, I did a simultaneous check using a Garmin Etrex Legend that I have had for some years. Starting both the 6220 and Garmin at the same time I compared them over a walk in open, essentially flat, country-side (in the UK) of around 1 hr 30 minutes. The 6220 was soon showing a noticably higher distances after just a few hundred feet. by the end of the walk the distance on the Garmin was 3.61 miles whilst SportTracker on the 6220 showed 5.27 miles! Seriously off!