Review on 🚴 XOSS G GPS Cycling Computer: Wireless Bike Speedometer, Odometer & Waterproof Road Bike MTB Bicycle Bluetooth (Combo2) - Advanced Features & Reliable Performance by Kyle Hood

As far as I can tell, the accuracy is pretty close. I've compared it to my phone's GPS and it's always about the same. I charge it after almost every ride and the only time it showed less than 50% charge was after a 2.5 hour ride with a 45 minute break in between when I didn't turn it off. It will stop automatically when you stop driving. Since speed and mileage are determined by GPS, there can sometimes be a slight delay when accelerating or decelerating, but on average it is very accurate. However, I would like to buy the G+ model as it allows you to add accessories like a wheel speed monitor or a heart rate monitor. Overall I am very happy with this purchase.