I chose the least expensive model for this device. The concept is a good one; however, the voice activation feature is inaccurate. It dials the incorrect party often. More times than not, it does not recognize my voice command, thus, I am reduced to using my handset to dial.The earpiece does not fit my ear and often shifts while I am driving (even though I have an average-shaped ear, close to my head). I press the device close in order to hear properly. In addition, I cannot tell when the device has turned itself off. The device is worth what I paid for it, no more. Do yourself a favor and buy the higher-priced model. Better yet, go to a store to experience the Bluetooth (or some other brand) before you purchase same. The engineer who designed this model needs to go back to the drawing-board.