Galaxy S4 now offers a seemingly unlimited number of device-control toggles, giving the perpetually power-conscious user an on-off switch for frequently (and not-so-frequently) used features, radios and controls within easy reach. On the subject of power, Galaxy S4's battery has been beefed up from 2100 mAh of the S3 to 2600 mAh, an increase of nearly 25 percent. And it made a difference. We used our Galaxy S4 test unit to play music, search the Web and read email for four straight hours while the battery declined by only 32 percent. The device worked a full blast for more than three additional hours and still had 22 percent of its charge remaining even as we wrote this.