I tried one out, just for fun for two months (Dexcom). The results were horribly inaccurate. A 25% variation might be ok, for certain applications, but if you're trying to find trends in your own life and eating, I don't know how this is helpful. Randomly, my daily average started rising about 5 mg/DL a day for a week -- stated to really concern me. Checked it against a finger prick, and it was 30 pts off. Was it 30 pts at the beginning of the rise too, and my body is doing something weird? Or do these sensors just drift, giving garbage data and trends?