Before I moved on to a Garmin watch, I used Runkeeper. IME, it was the most accurate app I used. I like the format/features of Nike+ the best, but on a open trail (no tree cover) in the middle of town, it isn't accurate. On my 4 mile run Thurs, I wan Nike+ with my Garmin, and it said I ran 4.8 miles compared to the 4 my Garmin said. (I know it was 4, since the mileage is marked on the trail. I just like my pace data.

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