Elevation data from Garmin Forerunners
I’ve had my Garmin Forerunner 305 for about 6 months now and in general love it. One thing that bugs me though is the elevation data it gathers tends to be fairly inaccurate (even in cases where the GPS signal is excellent and the measured distance covered is dead-on). This is really easy to spot if you do an out and back course for a workout by checking your elevation data and seeing if it looks symmetrical. If you use motionbased.com to store your workout data, you can apply their “gravity” service to have it auto-correct the elevation data on your uploaded workouts.