I have mow used this since very early Friday morning. It works exactly as it says. I was happy to come home after a heavy use day and have 50 to 55% battery life left. After two heavy use days amd more than usual for the test. I have had 70% battery left. I have the mobile network, WiFi and Bluetooth on all the time. While I was more that happy with the 9700 battery life I did not expect any or very little savings. I am amazed.
9700, 8520 & Pearl -T-Mobile