The One X has great battery life, so the fact that the Evo has an even larger 2,000mAh battery than its sibling (and no LTE to worry about) gave me great hope for its longevity. Unfortunately, I found that even getting a full day from the Evo took some finesse. Consider: I unplugged the phone at 4:15am, used it a bit on the way to the airport, turned it off on the plane until about 9, then streamed music through Rdio for about 40 minutes and did some browsing and tweeting from the device, with brightness at about 40 percent. By noon, I was down to 25 percent battery. We're running our official test now for more comparable results, but though in practice you should be able to get a full day's use from the phone with some battery TLC (and a lower brightness setting), I'm still a little underwhelmed with its performance.