One of the big reasons the Galaxy S5 edged out the iPhone 5s in our face-off is that its bigger battery lasts more than 2 hours longer on a charge. But Samsung didn't stop there. A new Ultra Power Savings Mode turns the screen to black and white, and tightly restricts app usage. The S5 is rated to last a whopping 24 hours in standby mode with only 10 percent juice left. That's impressive, but perhaps Apple could figure out a way to make the iPhone 6 last longer without radically changing the user experience.