A fall detection sensor is not a medical alert device you purchase solely on its own. Rather, you add the fall detection sensor to a medical alert system, either as a pendant or an activated feature on a mobile device. With this in mind, you should choose one of the best medical alert systems before you decide whether to add a fall detection sensor. I tested the call response times, quality of the call centers, speaker clarity and the fall detection sensors. After comparing costs with the performance, the GreatCall Mobile Lively earned my pick for the best fall detection sensor overall because this service provides the best medical alert system with the best fall detection performance.