I have attached an image of a run that I did on an iPhone3G versus Samsung Captivate. The former is on the bottom and the latter is on the top. I used the same tracking application on both. What is usually a ~3.4 mile run on an iPhone 3G was recorded as a 4.2 mile run on the Captivate. You can also see that the Samsung Captivate jumps around way too much and fails to locate me within a 100 meters at times.